Phoenix was able to continue growing during World War 2 as the city was the recipient of several military contracts. Once the war ended those contracts dried up leaving Phoenix in a small recession. During the 1950s Phoenix began experiencing rapid growth once again as air conditioning became widely available and the combination of healthy climate and natural beauty became strong pull factors. Phoenix's economy soon bounced back as well when increased defensive spending revived four military air fields located in the valley and private enterprises began to grow. Phoenix continued to expand as cheap land on the outskirts and an aggressive pro-annexation agenda gave way to the massive sprawl of subdivisions still seen in Phoenix today.

Serving as the center of the Aztec empire and New Spain, Mexico City has a very long and rich history of migration dating back to the 14th century. A political, cultural, and economic hub since its settlement, Mexico City has continuously attracted domestic migrants consisting of leaders, skilled laborers, and those looking for economic opportunity. This constant influx of rural-to-urban migration would create a vibrant and wealthy city center, with impoverished workers settling on the city's outskirts.

While the war for independence would affect Mexico City's built environment little, one of its largest shifts would occur shortly after with the election of Benito Juárez in 1858. Many of the church-held estates in the city would be confiscated and repurposed, with much being turned into housing for the working poor. The city would soon experience a large influx of domestic migration as the industrial revolution began, with elites of the city moving to the west side. In their absence, low-income families began to take up the deteriorating mansions of the city's downtown and east side, subdividing and repurposing them for multi-family housing and businesses.

In the midst of the Latin American Debt Crisis of the 1980s, Mexico City would see large amounts of factory closures and layoffs. In 1985, a severe earthquake would kill an estimated 10,000 people, with many of the deaths occurring in government-built housing. Around this time, Mexico would begin to take up more neoliberal economic policies, giving greater power and influence to the private sector. With a growth in imports, tourism, the service sector, and recent events, many began to see Mexico City less as a place of opportunity, and more as a place of corruption, crime, pollution, and overcrowding. All of these colluding factors would lead to the city having migration rates lower than estimated projections.