and loss of jobs. The effects of suburbanization were exacerbated by the small geographical size of St. Louis due to its earlier decision to become an independent city, and it lost much of its tax base. During the 19th and 20th century, most major cities aggressively annexed surrounding areas as residential development occurred away from the central city; however, St. Louis was unable to do so. Several urban renewal projects were built in the 1950s, as the city worked to replace old and substandard housing. Some of these were poorly designed and resulted in problems. One prominent example, Pruitt–Igoe, became a symbol of failure in public housing, and was torn down less than two decades after it was built. Since the 1980s, several revitalization efforts have focused on Downtown St. Louis. 21st century Urban revitalization continued in the new century. Gentrification has taken place in the Washington Avenue Historic District, Central West End and Forest Park Southeast neighborhoods. This helped St. Louis win the World Leadership Award for urban renewal in 2006. In 2017 the US Census Bureau estimated that St. Louis had a population of 308,826, down from 319,371 in 2010. In the 21st century, the city of St. Louis contains 11% of the total metropolitan population. (The top 20 U.S. metro areas have an average of 24% of their populations in their central cities.) St. Louis grew slightly during the early 2000s, but lost population from 2000 to 2010. Immigration has continued, with the city attracting Vietnamese, Latin Americans predominantly from Mexico, and Bosnians, who make up the largest Bosnian community outside of Bosnia and Herzegovina. Geography Cityscape Landmarks Architecture The architecture of St. Louis exhibits a variety of commercial, residential, and monumental architecture. St. Louis is known for the Gateway Arch, the tallest monument constructed in the United States at . The Arch pays homage to Thomas Jefferson and St. Louis's position as the gateway to the West. Architectural influences reflected in the area include French Colonial, German, early American, and modern architectural styles. Some notable post-modern commercial skyscrapers were built downtown in the 1970s and 1980s, including the One US Bank Plaza (1976), the AT&T Center (1986), and One Metropolitan Square (1989), which is the tallest building in St. Louis. One US Bank Plaza, the local headquarters for US Bancorp, was constructed for the Mercantile Bancorporation in the Structural expressionist style, emphasizing the steel structure of