China's largest temple and altar are found in Temple of Heaven, part of a 273 hectare park in Chongwen District today. Built in 1420, it was where Ming and Qing monarchs prayed for good harvests. Major structures are hall of Prayer for good Harvest, Imperial Vault of Heaven, Circular Altar, and Abstinence Palace. UNESCO endorsed Temple of Heaven as a world cultural heritage site in December 1998.