Touching the mottled old city wall, along the Danwei Bridge, from the Hall of Prayer for the Year to the echo wall, towards the mound. The echo wall is almost engraved by tourists, and the echo is also invalid. The heavenly core stone of Yuqiu is said to be a gem of Kunlun Mountain. It has its own mic. The emperor standing on it can shake the whole audience. After worshipping the wisdom of the ancients, it's interesting to sit among the trees and feel the life of the old people in modern Beijing.