In the 1900's Atlanta was a bustling railroad town but because of the increasing number of trolley cars, automobiles and pedestrians in the streets became too dangerous. The solution, build an viaduct over the existing street to carry local traffic leaving room for the trains to move "underground". Today the trains still run under the streets but this area has been transformed into a vibrant entertainment center. The Exchange and down the steps. This was the second level with the food court with all kinds of fast food places and over 75 vendors and unique shops running down the middle of the "tunnel" and lining the sides. It's about 75 feet wide (not including the stores) and runs for what seemed like blocks. The shops here definitely cater to the younger set. There is a game area with 20 or so arcade games and a stage where you can enjoy live music, group performances and cultural festivals. Downstairs on the first level is where all the restaurants and night clubs are. We spent about two hours walking around and eating our lunch at Johnny Rockets.