天坛 Temple of the Sky 天坛 天坛 was built in 1420 (Ming Dynasty) with a total area of 273 square KM. Emperors came to 天坛 every year to worship the sky, which was a very important ceremony. In Beijing City, there were also 地坛 (Earth )，日坛 (Sun) and 月坛 (Moon); but 天坛 was the largest and most important because ancient Chinese used to believe the sky was the god and emperors called themselves “the son of the sky”. http://www.youtube.com/watch?v=urPj06Lzes4 The Entrance of 天坛 This structure was where emperors rested before the ceremony, who needed to arrive 3 days in advance of the ceremony - no work, no entertainment, no rich food – a time for meditation. The Main Building 圆丘 (Round Hill) – There is a “Sky Heart Stone” in the middle of the hill. If you stand on the stone and speak, your voice will be much more resonant than usual. 回音壁 （Return Sound Wall） 回音壁 is a enclosed elliptical wall with a diameter of 61.5 M. It’s so well designed that if you stand at one side of the wall and speak softly, another person standing at the other end can hear you clearly.