The Red Tower of Beijing University is located at No. 29, Shatan North Street (now called Wusi Street) in Dongcheng District of Beijing City. It is east to Jingshan Park, north to the Forbidden City, and west to the Chinese Gallery. Now it has been turned into the office building of the National Cultural Relic Bureau.

The Red Tower was originally the first schoolhouse of Beijing University built in August 1918. It has an H shape, and faces the south. The building complex is 100 meters long from the east to the west, 14 meters deep from the south to the north, and its wing buildings are 34.34 meters long each from the south to the north. The total area is 10,000 square meters. It was built of red bricks thoroughly, hence the name Red Tower. The Red Tower used to include the school headquarters, the library, classrooms, and the presswork factory. A lot of celebrities and scholars such as Chen Duxiu, Li Dazhao, Lu Xun, Hu Shi, Qian Xuantong, Ma Yinchu and Li Siguang, etc, once taught in the school. To the north of the Red Tower lies the famous Democratic Square, which used to be the playground for the students.

At the beginning of 1918, Li Dazhao assumed the position of Director of the Library of Beijing University, where he founded the Study Group of the Marxism. The Marxism-Leninism was rapidly disseminated in Beijing University and spread to other regions. The Red Tower had become the center for the revolutionary activities in northern China. In 1919, it became the source of the May 4th Movement, a patriotic movement against the imperialism, and feudalism, which had exerted far-reaching influences on the Chinese Revolution. At that time, the Red Tower and the Democratic Square were the main venues of the patriotic movements, and the May 4^th Movement was initiated in the square.

From 1918 to 1919, Mao Zedong worked at the Library of Beijing University. The two rooms facing west at the southeast corner of the first floor used to be the office of Li Dazhao.