Xi'an Bell and Drum Towers, originally built in 1384 and rebuilt in the early Qing Dynasty, are located in the center of the city, adjacent to the Drum Tower and the Bell Tower. The Bell Tower is the largest and most important one of the three, and it is also the most representative one of the Tang Dynasty architectural style. The Bell Tower was used to sound the bells to mark the hours of the day, and the Drum Tower was used to sound the drums to mark the hours of the night. The two towers were also used to announce the time for the opening and closing of the city gates.