The Echo Wall

·The Echo Wall is located in the Temple of Heaven Park. It is the circular enclosure wall of the Imperial Vault of Heaven. The body of the wall is made of bricks from Linqing, Shandong Province, with the bricks ground and joined precisely, and it is covered with blue glazed cylindrical tile roofs on top.

·Because the curvature of the enclosure wall is very regular, it becomes an excellent reflector for sound waves. Two people can hear each other's voices when they stand at opposite ends of the wall respectively.
·They can call and respond to each other, ask and answer questions, and the sound lingers for a long time, which is truly interesting. One can feel the wisdom and wonder of the ancient people from it.