The Drum Tower (Gulou) was first built in 1272 during the reign of Kublai Khan and marked the center of the old Mongol Capital. Originally built of wood, the Drum Tower has been burned down several times and was rebuilt in 1420. Since then it has been repeatedly destroyed and restored. The Drum Tower is a two-story building with a height of 47 meters and 69 steep staircases. In ancient times the upper story of the Drum Tower used to house 25 drums, of which only the biggest one survives. The 24 smaller drums used to represent the 24 Solar Terms, while biggest one representing a year and has been destroyed partially. The present 25 drums are replicas according to the designs in the Qing Dynasty. There are seven rounds of drum beating ceremony being performed now. The performance is created according to the 24 Chinese Solar Terms to reflect changes of the four seasons as well as the agricultural life of ancient Chinese people. In the 1980s, after much repair, the Drum and Bell Towers were opened to the public. In ancient china, people divided the night into 5 Gengs, one Geng equals to 2 hours. Starting from Emperor Qianlong (1711-1799), the time was announced only twice in the evening: the first time was at the first Geng (19:00-21:00), the Drum would be beaten to mark the end of transportation with all the city gates closed; the second time would be at the fifth Geng (03:00-05:00), the Bell would be stroke and all the city gates would be opened. Colloquially, Chinese people called it “Down Bell, Dusk Drum”. The way of beating the Drum and striking the Bell is similar: 18 times of normal speed, 18 times faster, 18 times slower and repeat that again for 108 times striking or beating. Because the ancient Chinese used 108 to represent a year which is formed by 12 months, 24 Solar Terms and 72 Hou (five days).