[Billy]

The Temple is surrounded by two cordons of walls; the outer wall has a taller, semi-circular northern end, representing Heaven, and a shorter, rectangular southern end, representing the Earth.
All the buildings within the Temple have special dark blue roof tiles, again representing the Heaven.
The Altar of Heaven was constructed with details representing the number nine, the representative number of the Emperor.
If you stand at the centre of the platform and clap your hands, you can hear the echo because of the concavity of the surrounding wall.
The House of Heavenly Lord is surrounded by a curved wall, 6 metres tall and 32.5 metres in radius. It is nicknamed the 'Echo Wall' because a person at one end of the wall can hear the voice of a person at the other end of the wall.
The Hall of Annual Prayer is 32 metres in diameter and 38 metres tall. It has four inner, twelve middle and twelve outer pillars, representing the four seasons, twelve months and twelve traditional Chinese hours respectively.
The Hall of Prayer for Good Harvests was built without a single nail.
Some Chinese Christians consider the Temple of Heaven as a tribute to the Christian God, believing that the belief in Heaven to be an unarticulated reverence for the true God.