The Echo Wall of the Temple of Heaven
Whisper into a round wall at Beijing's Temple of Heaven, and a friend on the far side, 60 metres away, hears you clearly.
What was reported
The Imperial Vault of Heaven, part of the Temple of Heaven complex in Beijing where emperors prayed for good harvests, is surrounded by a smooth circular wall about 65 metres across. It is known as the Echo Wall.
Two people standing at opposite sides can whisper to each other along the wall and hear every word. Nearby, the Triple Echo Stones are said to return a clap once, twice or three times depending on where you stand.
Explanations offered
It is a whispering gallery, like Gol Gumbaz in India or St Paul's Cathedral in London. Sound waves hug the smooth, curved, hard surface of the wall and travel around it with little loss. The echoes from the stones come from sound bouncing off the surrounding walls.
- When
- Built in the 1500s
- Where
- Temple of Heaven, Beijing, China
- Witnesses
- Visitors every day
- Status
- Explained
Famous cases are real, widely reported events. Each file sets out what witnesses said and the explanations that have been offered, without taking a side.