Atlanta () is the capital and most populous city of the U.S. state of Georgia. With a 2020 census population of 498,715, it is the 38th most populous city in the United States. The city serves as the cultural and economic center of the Atlanta metropolitan area, home to more than six million people and the ninth-largest metropolitan area in the nation. Atlanta is the seat of Fulton County, the most populous county in Georgia. Situated among the foothills of the Appalachian Mountains, Atlanta features unique topography that includes rolling hills and the most dense urban tree coverage in the United States.Atlanta was originally founded as the terminus of a major state-sponsored railroad. With rapid expansion, however, it soon became the convergence point among multiple railroads, spurring its rapid growth. The city's name derives from that of the Western and Atlantic Railroad's local depot, signifying the town's growing reputation as a transportation hub. Toward the end of the American Civil War, in November 1864, the city was almost entirely burned to the ground in General William T. Sherman's March to the Sea. However, the city rose from its ashes and quickly became a national center of commerce and the unofficial capital of the "New South". During the 1950s and 1960s, Atlanta became a major organizing center of the civil rights movement, with Martin Luther King Jr., Ralph David Abernathy, and many other locals playing major roles in the movement's leadership. During the modern era, Atlanta has attained international prominence as a major air transportation hub, with Hartsfield–Jackson Atlanta International Airport being the world's busiest airport by passenger traffic since 1998.With a gross domestic product (GDP) of $406 billion, Atlanta has the 10th largest economy in the U.S. and the 20th largest in the world. Atlanta's economy is considered diverse, with dominant sectors that include aerospace, transportation, logistics, film and television production, media operations, professional and business services, medical services, and information technology. The gentrification of some Atlanta neighborhoods, initially spurred by the 1996 Summer Olympics, has intensified in the 21st century with the growth of the Atlanta Beltline. This has altered the city's demographics, politics, aesthetic, and culture.