Yandun, Historical monument in Dongcheng District, China.

Yandun is a single square brick platform about 9 metres high, its base 14.87 metres per side and its top 13.9 metres per side, standing on the west side of Yongdingmenwai Dajie in Dongcheng District. Two stone doors at the northwest corner open onto 45 steps leading to a stone altar and an 8-metre stele.

Yandun began as an earthen platform under the Yuan dynasty, when it served as the southern of Beijing's Five Towns, a fire-responding beacon tower. In 1553, during the construction of the outer city under the Ming, the platform was encased in brick. It was listed as a Beijing municipal cultural relic in 1984, when it stood inside a warehouse courtyard; the surrounding Yandun Park opened in the 1990s, and in 2004 the monument was cleared of obstructing buildings and rubbish.

Yandun is also called Yandun, meaning "smoke mound", because it was built as a beacon tower to match the south, the direction associated with fire in the Five Elements. Qing dynasty poet Yang Jingshan described it in a poem as a stone pillar standing by the sandy road, facing the site of the former Lizheng Gate of the Yuan capital.

Yandun stands on the west side of Yongdingmenwai Dajie, about half a li south of Yongdingmen and just south of the Yongdingmen railway bridge. The stone doors at its northwest corner open onto 45 steps to the top; the surrounding Yandun Park was cleared in 2009 for the Yongdingmen station exit of Metro Line 14.

Yandun was long hidden inside the courtyard of a warehouse and by surrounding buildings and rubbish; it only became fully visible from Yongdingmenwai Dajie in 2004 during the South Central Axis road project. In 2009 over a hundred trees of the surrounding park were transplanted for the Line 14 metro exit, but the platform itself stayed in place.