A few steps north of the Circular Mound Altar is the Echo Wall. This oval-shaped encasement around the Imperial Vault of Heaven is named because of its amazing acoustical design. Two people standing at either side of its 633 foot circumference can conduct a normal conversation thanks to the wall’s sound transmission abilities. The wall also has Three Echo Stones. Say something on the first one to hear one echo. The second and third stones produce the corresponding number of echoes.
