and is water. The city is situated in the Deep South of the southeastern United States among the foothills of the Appalachian Mountains. At above mean sea level, Atlanta has the highest elevation among major cities east of the Mississippi River. Atlanta straddles the Eastern Continental Divide. Rainwater that falls on the south and east side of the divide flows into the Atlantic Ocean, while rainwater on the north and west side of the divide flows into the Gulf of Mexico. Atlanta developed on a ridge south of the Chattahoochee River, which is part of the ACF River Basin. The river borders the far northwestern edge of the city, and much of its natural habitat has been preserved, in part by the Chattahoochee River National Recreation Area. Atlanta is 21 miles (33km) southeast of Marietta, 27 miles (43km) southwest of Alpharetta, 146 miles (234km) southwest of Greenville, South Carolina, 147 miles (236km) east of Birmingham, Alabama, and 245 miles (394km) southwest of Charlotte, North Carolina. Atlanta is sometimes called "City of Trees" or "city in a forest", despite having lost approximately of trees between 1973 and 1999. Cityscape Most of Atlanta was burned during the American Civil War, depleting the city of a large stock of its historic architecture. Yet architecturally, the city had never been traditionally "southern" because Atlanta originated as a railroad town, rather than a southern seaport dominated by the planter class, such as Savannah or Charleston. Because of its later development, many of the city's landmarks share architectural characteristics with buildings in the Northeast or Midwest, as they were designed at a time of shared national architectural styles. During the late 20th century, Atlanta embraced the global trend of modern architecture, especially for commercial and institutional structures. Examples include the State of Georgia Building built in 1966, and the Georgia-Pacific Tower in 1982. Many of the most notable examples from this period were designed by world renowned Atlanta architect John Portman. Most of the buildings that define the downtown skyline were designed by Portman during this period, including the Westin Peachtree Plaza and the Atlanta Marriott Marquis. In the latter half of the 1980s, Atlanta became one of the early homes of postmodern buildings that reintroduced classical elements to their designs. Many of Atlanta's tallest skyscrapers were built in this period and style, displaying tapering spires or otherwise ornamented crowns, such as One Atlantic Center (1987),