Tian'Tan - literally the Altar of Heaven is a complex of Taoist buildings situated in southeastern urban Beijing. Covering 2.73 sq km of parkland - the largest temple complex in the world - it comprises of 3 main group of constructions viz. The Earthly Mount, House of Heavenly Lord and Hall of Prayer for Good Harvests

All the buildings within the Temple have special dark blue roof tiles, again representing the Heaven

The Hall of Prayer for Good Harvests was built without a single nail, though it's all wood