Introduction to Yunyan Tower: Yunyan Tower, also known as Manmengding Tower. Yunyan Tower was built in 1947 and completed in 1955. The bottom of the tower covers an area of 400 square meters and is a multi-story brick-concrete structure. It is composed of a main tower (20 meters high) and 40 small towers, all in a cone shape. It is located on Yunyan Mountain, 1 km east of Yingjiang County.