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By the end of this lesson, students will be able to (per CED LO SPS-6.A):
- Explain causes and effects of geographic change within urban areas (per LO SPS-6.A).
- Identify housing discrimination practices including redlining, blockbusting, and affordability barriers, and describe their visible legacy on urban landscapes (per EK SPS-6.A.1).
- Explain access-to-services problems, rising crime, environmental injustice, and the growth of disamenity zones or zones of abandonment (per EK SPS-6.A.1).
- Describe the growth of squatter settlements and conflicts over land tenure in large cities worldwide (per EK SPS-6.A.2).
- Evaluate responses to economic and social challenges, including inclusionary zoning and local food movements (per EK SPS-6.A.3).
- Analyze the positive AND negative consequences of urban renewal and gentrification (per EK SPS-6.A.4).
- Explain how functional and geographic government fragmentation complicates urban problem-solving (per EK SPS-6.A.5).
- Apply Skill 4.E: interpret maps, aerial images, and street-level landscapes to identify the physical signatures of urban challenge processes.
Key Concepts
Unit 6 Lesson 10 is the broadest lesson in the unit. LO SPS-6.A is supported by five Essential Knowledge items — from housing discrimination to government fragmentation. Rather than treating each separately, think of them as four linked questions:
- Problem inventory (EK SPS-6.A.1 and SPS-6.A.2): what economic, social, and environmental challenges do urban populations face?
- Response inventory (EK SPS-6.A.3 and SPS-6.A.4): what tools do cities use, and what do those tools do well and poorly?
- Governance constraint (EK SPS-6.A.5): why are coordinated responses so difficult?
- Skill 4.E lens: every challenge has a landscape signature. Learning to read those signatures is the heart of this lesson.
Four more Essential Knowledge items expand the picture. EK SPS-6.A.2 adds squatter settlements and land tenure conflict. EK SPS-6.A.3 names inclusionary zoning and local food movements as responses. EK SPS-6.A.4 requires students to analyze both positive and negative consequences of urban renewal and gentrification. EK SPS-6.A.5 introduces functional and geographic fragmentation of governments as a structural obstacle to coordinated response.
Skill 4.E asks students to explain how maps, images, and landscapes illustrate or relate to geographic principles, processes, and outcomes. Every section below identifies the visible landscape evidence an AP student should be able to recognize.
Housing Discrimination (EK SPS-6.A.1, part 1)
Three named practices: redlining, blockbusting, and the broader affordability crisis. Each produces durable patterns still visible today.
Federal denial of mortgage insurance by neighborhood
In the 1930s the federal Home Owners' Loan Corporation (HOLC) graded urban neighborhoods A (green, "best") through D (red, "hazardous"). Black, immigrant, and mixed-race neighborhoods were almost universally colored red regardless of housing quality or resident income. Federal mortgage insurance flowed to green areas and was denied in red ones. Private lenders followed the same maps.
Decades of disinvestment stripped wealth from redlined blocks. Landlord-owned rental replaced owner-occupied housing; property upkeep declined; public services thinned.
Profiteering from engineered racial turnover
Real-estate agents deliberately induced white homeowners to sell below market value by stoking fear that Black families were "moving in." Panicked sales transferred homes to the agent at discount; the agent then resold to Black buyers at a premium. The practice accelerated white flight in mid-20th-century US cities, often concentrated in a few weeks across a single block.
Blockbusting combined with redlining: Black buyers, denied conventional mortgages, often accepted predatory contract-for-deed financing, in which missing a single payment forfeited the home.
Rent burden exceeding 30% of household income
Federal standards consider households "rent-burdened" when housing costs exceed 30% of income and "severely burdened" above 50%. In most coastal US cities, over 50% of renters are rent-burdened; in New York and San Francisco the figure exceeds 55%. Construction has not kept pace with demand in the economically strongest metros.
Causes are structural: restrictive zoning, construction-cost inflation, limited federal housing subsidy, and the concentration of high-wage jobs in a handful of metros. Effects cascade: longer commutes, crowding, doubling up, homelessness.
Access to Services, Crime, and Environmental Injustice (EK SPS-6.A.1, part 2)
When people move within a city, services do not always follow. Supermarkets close in disinvested neighborhoods; health clinics consolidate in wealthier ones; bank branches shrink in formerly redlined areas. The result is a geography of service deserts.
Food deserts
The US Department of Agriculture defines a food desert as a low-income census tract where a significant share of residents live more than one mile (urban) or ten miles (rural) from a full-service grocery store. By that standard roughly 13% of US census tracts are food deserts, disproportionately in formerly redlined urban neighborhoods and remote rural counties. Residents rely on convenience stores and fast food, raising rates of diet-related disease.
Healthcare and banking deserts
Parallel patterns apply to primary-care physicians, dental care, mental-health services, and full-service bank branches. Where banks withdraw, check-cashing outlets and payday lenders fill the gap at far higher cost. The landscape signal is direct: commercial corridors in affluent neighborhoods feature independent pharmacies, full-service groceries, and bank branches; corridors in disinvested neighborhoods feature dollar stores, fast food, and check-cashing windows.
Rising crime
Crime is concentrated geographically. A small number of hot-spots in most US cities account for a large majority of violent incidents. Concentrated poverty, housing abandonment, and weak formal institutions all correlate with elevated crime rates. Crime in turn accelerates population loss, creating a feedback loop with disinvestment.
Environmental injustice
Environmental injustice describes the disproportionate exposure of minority and low-income communities to pollution, toxic facilities, and environmental hazards. EK SPS-6.A.1 names it explicitly. Cases include:
- Cancer Alley, Louisiana: an 85-mile stretch of the Mississippi River between Baton Rouge and New Orleans hosts more than 150 petrochemical plants. Predominantly Black small towns along the corridor report cancer rates up to 50x the national average.
- Flint, Michigan: a 2014 switch to Flint River water without corrosion control leached lead from aging pipes into the drinking supply of a majority-Black city. Elevated blood-lead levels were documented in children over 18 months before the state acknowledged the crisis.
- Urban heat islands: formerly redlined neighborhoods in cities from Baltimore to Portland experience summer temperatures 5-12°F hotter than nearby green-rated neighborhoods because of reduced tree canopy and greater impervious surface.
Disamenity Zones and Zones of Abandonment (EK SPS-6.A.1, part 3)
Urban areas where population and services have collapsed
A disamenity zone is the poorest, least-served part of a city — often built on marginal land (steep slopes, flood plains, near industrial pollutants). In Latin American city models (Griffin-Ford) disamenity zones appear in specific ring positions. A zone of abandonment is a neighborhood where population loss and disinvestment have reached the point that buildings are demolished or left derelict and commercial activity has largely ceased.
The two concepts overlap but differ in origin. Disamenity zones often grow outward from rapid rural-urban migration onto unwanted land. Zones of abandonment typically result from industrial decline and white flight in older US cities.
US case: Detroit and the post-industrial belt
Detroit's population peaked at 1.85 million in 1950 and had fallen below 640,000 by 2020 — the largest absolute decline of any US city. Block-level abandonment reached scales visible from aircraft: vast prairies of vacant lots punctuated by occupied homes. Similar but less extreme abandonment affects parts of Baltimore, Cleveland, St. Louis, Youngstown, and Gary.
The landscape cues are unmistakable in Street View: chain-link fencing around vacant lots, "No Trespassing" signs on brick row houses with plywood windows, weeds growing through sidewalks, churches and schools closed, bus routes truncated. These are the visual markers Skill 4.E asks students to read.
Squatter Settlements and Land-Tenure Conflict (EK SPS-6.A.2)
EK SPS-6.A.2 in full: Within large cities, squatter settlements and conflicts over land tenure have been on the rise.
Housing built without legal ownership of the land
A squatter settlement is a neighborhood built and occupied without formal title to the underlying land. Residents lack legal protection against eviction and usually lack municipal services. UN-Habitat estimates roughly one billion people live in such settlements globally — nearly one in every four urban residents. Numbers are rising with rapid urbanization across sub-Saharan Africa and South Asia.
Regional names: favelas (Brazil), comunas and tugurios (Colombia), barriadas and pueblos jovenes (Peru), villas miseria (Argentina), katchi abadis (Pakistan), bustees (India and Bangladesh), gecekondu (Turkey). Kibera (Nairobi) and Dharavi (Mumbai) are among the largest.
Conflict over land tenure
Tenure conflict takes several forms. Governments may attempt forced eviction to make land available for roads, Olympic venues, or commercial redevelopment. Private owners whose unfenced land has been informally occupied sue for removal. Upgrading programs formalize tenure by granting titles to long-term residents — Peru's COFOPRI program has issued over 1.5 million titles since 1996.
Formalization has mixed effects. Titled residents can borrow against their homes and invest in upgrades, and they are protected from arbitrary eviction. But formalization also exposes residents to property taxes, market-rate displacement, and predatory lending.
Not only Global South
The US has informal settlements too, though usually called by different names. Colonias along the Texas-Mexico border, migrant-worker camps in California's Central Valley, and rural mobile-home parks in Appalachia share key features: informal or insecure tenure, missing services, ambiguous legal status. The phenomenon named in EK SPS-6.A.2 is global.
Inclusionary Zoning (EK SPS-6.A.3, part 1)
EK SPS-6.A.3 in full: Inclusionary zoning and local food movements are among the responses cities use to confront economic and social challenges.
Requiring affordable units within new developments
Inclusionary zoning is a municipal regulation that requires new residential projects above a certain size to reserve a percentage of units (typically 10-25%) for households earning below a set income threshold, at below-market rents or prices. The units must be integrated into the same building or neighborhood as market-rate units.
The approach aims to expand affordable housing supply without direct public subsidy and to prevent economic segregation by placing affordable units in high-opportunity neighborhoods.
Tradeoffs
Inclusionary zoning has known limitations. If the required affordable-unit share is set too high, developers may build fewer total units or shift to commercial uses, actually reducing overall housing supply. The policy works best as part of a broader package that includes density bonuses, streamlined permitting, and public housing investment.
Landscape signal: new multi-story apartment buildings in gentrifying neighborhoods with a visible rental-office sign listing both market and income-restricted rents; a uniform building exterior with no visible class distinction between unit types (by design, to avoid stigma).
Local Food Movements (EK SPS-6.A.3, part 2)
Producing, distributing, and consuming food within a region
Local food movements include urban farming, community gardens, farmers markets, community-supported agriculture (CSA), school-garden programs, rooftop agriculture, and food-policy councils. The movement addresses food-desert access, reduces food-miles, reconnects urban residents to production, and supports small regional farms.
Urban farms on reclaimed land
Detroit's abandonment crisis has produced one of the world's most visible urban-farming experiments. Nonprofits and cooperatives have converted thousands of vacant lots into productive gardens and farms, producing fresh vegetables for neighborhoods without grocery stores. The landscape signal is unmistakable: raised beds, hoop houses, and orchard rows standing where row houses once stood.
Policy infrastructure
More than 300 US cities and counties have formed food-policy councils, advisory bodies that coordinate government, producers, and community groups around food-system issues. Cities including Baltimore, Toronto, and Minneapolis have produced formal food-system plans that integrate zoning, procurement, and public-health goals.
Urban Renewal and Gentrification (EK SPS-6.A.4)
EK SPS-6.A.4 in full: Both urban renewal and gentrification carry positive and negative consequences. The CED is explicit: students must be able to analyze BOTH sides of BOTH processes.
Government-led clearance and redevelopment (1949-1970s)
Urban renewal refers primarily to federal programs authorized by the US Housing Act of 1949 (and parallel programs elsewhere). Municipalities used eminent domain to acquire entire "blighted" neighborhoods, demolished the existing fabric, and rebuilt with freeways, high-rise public housing, convention centers, or superblock commercial projects.
Positive consequences of urban renewal
- Slum-clearance removed genuinely substandard housing and reduced tuberculosis and fire risk.
- Interstate freeway construction, funded alongside renewal, knit cities to national networks.
- Public health improvements from modern water and sewer infrastructure in rebuilt districts.
- Some projects (Philadelphia's Society Hill) successfully revitalized historic neighborhoods.
Negative consequences of urban renewal
- Disproportionate destruction of minority neighborhoods; James Baldwin's widely-quoted phrase "Negro removal" captured the pattern.
- Freeways severed walkable neighborhoods and created lasting barriers (Oakland's I-980, Miami's I-95 through Overtown).
- High-rise public housing concentrated poverty and proved difficult to maintain (Pruitt-Igoe, Cabrini-Green, Robert Taylor Homes all eventually demolished).
- Loss of social fabric that dense, low-rise neighborhoods had maintained over generations. Jane Jacobs's The Death and Life of Great American Cities (1961) became the classic critique.
Market-led in-migration of higher-income residents
Gentrification is the process in which higher-income, typically more-educated residents move into previously lower-income urban neighborhoods, raising property values and reshaping commercial character. Sociologist Ruth Glass coined the term in 1964 observing London's Islington; the phenomenon accelerated in US cities from the 1970s onward.
Positive consequences of gentrification
- Reinvestment reverses decades of disinvestment; building stock rehabilitated rather than demolished.
- Population stabilization or growth reverses loss in previously declining neighborhoods.
- Tax base expands, funding schools, parks, and services.
- Reduced vacancy lowers certain crime categories; improved street-level activity ("eyes on the street").
- New small businesses, some growing from within existing communities.
Negative consequences of gentrification
- Displacement of long-term residents through rent increases, lease non-renewals, and condo conversions.
- Loss of neighborhood commercial character as rents rise beyond reach of long-standing businesses.
- Erosion of social networks built over decades (churches, mutual-aid groups, cultural institutions).
- Widening economic sorting across the metropolitan area as displaced residents relocate to lower-opportunity neighborhoods.
- Monetization of cultural distinctiveness followed by its homogenization.
Landscape signal for gentrification: Skill 4.E candidates include restored brownstone facades next to not-yet-restored ones on the same block, new coffee shops alongside 1970s-era businesses, scaffolding for renovations, banners announcing condo conversions, boutique retail in former corner stores.
Government Fragmentation (EK SPS-6.A.5)
EK SPS-6.A.5 in full: Tackling urban issues is complicated by the functional and geographic fragmentation of government — the way agencies and institutions are spread across state, county, city, and neighborhood levels.
Authority scattered across many jurisdictions
US metropolitan areas are divided among many separately-incorporated municipalities, independent school districts, county governments, special-purpose districts (water, transit, parks, flood control, pest control), and state and federal agencies. The typical major metro contains hundreds of such bodies. Coordinated action is institutionally difficult because no single authority has jurisdiction over the entire problem space.
Functional vs geographic fragmentation
The CED distinguishes two dimensions:
- Functional fragmentation: separate agencies responsible for related problems. Housing, homelessness services, addiction treatment, and mental-health services are usually administered by different departments, even within the same city — and often at different levels of government.
- Geographic fragmentation: problems cross political boundaries. Homelessness flows between cities. Air pollution crosses county lines. Water systems span multiple jurisdictions. School-district boundaries enforce de facto segregation because school assignment tracks residence.
Consequences
- Race-to-the-bottom dynamics: individual municipalities restrict low-income housing, shifting the burden to neighbors.
- Transit stops at municipal boundaries even when commuting patterns do not.
- Duplicated administrative overhead across many small police, fire, and school districts.
- Fiscal disparity: wealthy suburbs retain tax base while central cities absorb regional service costs.
Structural responses
Several models attempt to overcome fragmentation:
- Consolidated city-county government: Miami-Dade (Florida), Indianapolis-Marion (Indiana), Nashville-Davidson (Tennessee), Louisville-Jefferson (Kentucky) merged city and county into single governments.
- Regional government: Portland (Oregon) Metro is the only directly-elected regional government in the US, with authority over land-use planning and transportation.
- Unitary city-state: Singapore operates as a single-tier government for its entire territory, eliminating fragmentation entirely (at the cost of political autonomy for sub-areas).
- Metropolitan planning organizations (MPOs): federally required regional bodies that coordinate transportation planning across US metros but without taxing authority.
Skill 4.E · Reading Challenge Landscapes
Skill 4.E requires students to explain how maps, images, and landscapes illustrate or relate to geographic principles, processes, and outcomes. This lesson's concepts have strong visual signatures. Train students to look for them.
From historical maps
- HOLC 1930s "Residential Security" maps color-coded A (green) through D (red). Overlay with 2020 census data on tree canopy, asthma rates, or property values and the correlation is immediate.
- Sanborn fire-insurance maps show pre-renewal building footprints; compare with modern aerial imagery to identify razed neighborhoods.
From aerial and satellite imagery
- Favela geometry: dense, irregular rooflines with narrow footpaths, often climbing steep slopes. Contrast with the planned rectilinear grid of surrounding formal neighborhoods.
- Urban renewal footprints: superblocks with single land use (high-rise or freeway), walled off from surrounding street grid.
- Zones of abandonment: vacant parcels forming checkerboard or prairie patterns, visible only from altitude.
From street-level imagery
- Gentrification: restored facades next to unrestored; construction scaffolding; coffee shops alongside older businesses; banners advertising condo conversions.
- Formerly redlined areas: missing street trees, vacant lots, absence of full-service groceries or bank branches, proliferation of check-cashing and dollar stores.
- Squatter settlements: self-built masonry with no uniform facade line, informal electrical connections, narrow pathways.
Country Case Studies
Four cases, one per EK cluster: abandonment and urban renewal legacy; squatter settlement; gentrification; informal-tenure megacity.
United States · Detroit Abandonment & Renewal Legacy
Detroit exemplifies EK SPS-6.A.1's "zones of abandonment" and the legacy of both urban renewal (Black Bottom razed for I-375 in 1959) and redlining. It also hosts one of the world's largest urban-farming experiments on reclaimed lots — a case study in local food movements (EK SPS-6.A.3) built atop the ruins of abandonment.
Country page →
Brazil · Rio de Janeiro Favelas
Rio's favelas exemplify EK SPS-6.A.2's squatter settlements and land-tenure conflict. Rocinha, the largest, houses an estimated 100,000-200,000 residents on a hillside facing Ipanema. Government "pacification" programs, Olympic-venue evictions, and upgrading initiatives (Favela-Bairro, Morar Carioca) illustrate the contested politics of informal tenure.
Country page →United States · San Francisco Gentrification
San Francisco's Mission District illustrates EK SPS-6.A.4's positive-AND-negative requirement. Two decades of tech-sector growth have reinvested heavily in the neighborhood (positive) while driving out long-standing Latino residents and independent businesses (negative). San Francisco has also been a pioneer of inclusionary zoning in response (EK SPS-6.A.3).
Country page →
India · Mumbai's Dharavi
Dharavi is among the world's largest and densest informal settlements and a textbook case for EK SPS-6.A.2. Residents produce leather goods, recycled plastics, and pottery at industrial scale despite insecure tenure. Successive government redevelopment proposals have stalled because of intense conflict between residents, developers, and advocacy groups.
Country page →Discussion Questions
- Per EK SPS-6.A.1, redlining, blockbusting, and affordability are named housing challenges. Redlining was formally outlawed in 1968. Why do its effects remain visible in US cities today? Cite at least three landscape features that Skill 4.E would identify.
- EK SPS-6.A.2 identifies squatter settlements as an increasing global phenomenon. Compare the causes of informal settlement growth in Rio, Mumbai, and Nairobi. How similar or different are the underlying drivers?
- EK SPS-6.A.3 names inclusionary zoning as a response. Under what conditions does the policy expand affordable housing, and under what conditions does it reduce total housing supply? What does each outcome tell you about local housing markets?
- EK SPS-6.A.4 requires analysis of BOTH positive and negative consequences of gentrification. Choose a single neighborhood you know (or can research) and write one paragraph on each side. Which side do you find more compelling, and why?
- EK SPS-6.A.4 also asks about urban renewal. Robert Moses built a great deal in New York; Jane Jacobs opposed him. With 60 years of hindsight, whose approach looks better? Is the answer the same for every case, or does it depend on the project?
- Apply Skill 4.E: using online aerial imagery of your own metropolitan area, identify one location likely to be a zone of abandonment, one likely to be a zone of gentrification, and one likely to contain affordable units from inclusionary zoning. What visual cues supported each identification?
Classroom Activities
HOLC Map Overlay
Using the Mapping Inequality digital archive, students select a 1930s HOLC "residential security" map for their home city or a chosen US city. They overlay it onto present-day data layers (tree canopy, surface temperature, asthma rates, median property value) available from the local government open-data portal or ESRI Living Atlas. Students annotate at least five census tracts where redlining's legacy is visible, citing specific numbers. Discussion: why did the pattern persist across 90 years? Direct application of Skill 4.E and EK SPS-6.A.1.
Favela Field Study via Street View
Students use Google Street View to "walk" through Rocinha or another Rio favela along a pre-selected 500-meter route. They catalog observations in four columns: building materials, utility connections, commercial activity, accessibility (widths and conditions of walkways). They compare with a parallel walk through Ipanema nearby. The comparison surfaces visible markers of informal tenure (EK SPS-6.A.2) and illustrates Skill 4.E. Extension: repeat for Dharavi (Mumbai) or Kibera (Nairobi) and compare.
Vocabulary
Standards Alignment
Draft alignment — pending educator review. AP HG codes correspond to the official College Board Course and Exam Description (Effective Fall 2020, V.1). Statements below are paraphrased in CountryReports' own voice; refer to the College Board's published CED for verbatim wording.
Suggested Skill
Enduring Understanding
Learning Objective
Essential Knowledge
AP® and Advanced Placement® are registered trademarks of the College Board. The College Board was not involved in the production of this material and does not endorse it. Standards statements above are paraphrased; codes refer back to the official College Board CED, the NCSS C3 Framework, the Common Core State Standards, and other cited frameworks.
AP Practice Questions
- (A) Blockbusting.
- (B) Gentrification.
- (C) Redlining.
- (D) Inclusionary zoning.
- (E) Urban renewal.
Correct: (C) Redlining. The federal Home Owners' Loan Corporation (HOLC) produced the 1930s maps; red-coded areas were denied federally-insured mortgages. (A) Blockbusting was a real-estate practice, not federal. (B) Gentrification is in-migration, not mapping. (D) Inclusionary zoning is a policy response (EK SPS-6.A.3). (E) Urban renewal is post-1949 clearance (EK SPS-6.A.4).
Scoring: 2 points for urban renewal definition + era (federal clearance programs authorized by 1949 Housing Act, most active 1949-1970s); 2 points for gentrification definition + example (in-migration of higher-income residents into lower-income neighborhoods; examples include San Francisco Mission, Brooklyn Williamsburg, DC U Street, Austin East Side, Boston South End); 2 points for two positive consequences (reinvestment, reduced vacancy, improved tax base, rehabilitation of aging stock, population stabilization); 2 points for two negative consequences (displacement, rent increases, loss of cultural character, erosion of social networks, loss of neighborhood-serving businesses); 2 points for two landscape features (restored facades next to unrestored; construction scaffolding; new coffee shops alongside older businesses; condo-conversion banners; boutique retail replacing corner stores). Full credit requires explicit analysis of BOTH positive AND negative per the CED language.