The Temple of Heaven is located in the southern part of Beijing city, and it was built in 1420 during Ming dynasty. It is surrounded by two rings of walls and covers an area of 273 hectares, and it is the most holy of Beijing's Imperial temples. In Ming and Qing dynasty, emperors went to The Temple of Heaven twice a year to worship heaven and pray for fine rain and good harvests. There are the circular Echoing Wall and the Triple Sound Stones inside.