A city's population is its basic structure, and the number of residents varies based on where it is located. The earliest cities were built near rivers and seaports, and served as strategic locations for trade. Boston and other cities like New Amsterdam and Charles Town were established for these purposes. These cities were often small, with irregular street patterns. The houses were often made of stone, which gave them a medieval appearance. In contrast, modern cities have well-maintained streets with a well-defined grid system.
The Atlanta metropolitan area's population is comprised of two main groups: whites and African Americans. Whites dominate the suburban population, but African Americans have a strong presence within the city. Suburban growth, meanwhile, has contributed to the city's environmental problems. The area has lost over 190,000 acres of trees since 1988.