following the capture of Chattanooga and began its invasion of north Georgia. The region surrounding Atlanta was the location of several major army battles, culminating with the Battle of Atlanta and a four-month-long siege of the city by the Union Army under the command of General William Tecumseh Sherman. On September 1, 1864, Confederate General John Bell Hood decided to retreat from Atlanta, and he ordered the destruction of all public buildings and possible assets that could be of use to the Union Army. On the next day, Mayor James Calhoun surrendered Atlanta to the Union Army, and on September 7, Sherman ordered the city's civilian population to evacuate. On November 11, 1864, Sherman prepared for the Union Army's March to the Sea by ordering the destruction of Atlanta's remaining military assets. Reconstruction and late 19th century After the Civil War ended in 1865, Atlanta was gradually rebuilt during the Reconstruction era. The work attracted many new residents. Due to the city's superior rail transportation network, the state capital was moved from Milledgeville to Atlanta in 1868. In the 1880 Census, Atlanta had surpassed Savannah as Georgia's largest city. Beginning in the 1880s, Henry W. Grady, the editor of the Atlanta Constitution newspaper, promoted Atlanta to potential investors as a city of the "New South" that would be based upon a modern economy and less reliant on agriculture. By 1885, the founding of the Georgia School of Technology (now Georgia Tech) and the Atlanta University Center, a consortium of historically black colleges made up of units for men and women, had established Atlanta as a center for higher education. In 1895, Atlanta hosted the Cotton States and International Exposition, which attracted nearly 800,000 attendees and successfully promoted the New South's development to the world. 20th century During the first decades of the 20th century, Atlanta enjoyed a period of unprecedented growth. In three decades' time, Atlanta's population tripled as the city limits expanded to include nearby streetcar suburbs. The city's skyline grew taller with the construction of the Equitable, Flatiron, Empire, and Candler buildings. Sweet Auburn emerged as a center of black commerce. The period was also marked by strife and tragedy. Increased racial tensions led to the Atlanta Race Riot of 1906, when whites attacked blacks, leaving at least 27 people dead and over 70 injured, with extensive damage in black neighborhoods. In 1913, Leo Frank, a Jewish-American factory