When night falls on weekends or important festivals, the wooden Hall of Prayer for Good Harvests lights up to become the most eye-catching presence in the Temple of Heaven, a 604-year-old royal altar and UNESCO world heritage site in Beijing. The Hall of Prayer for Good Harvests, a magnificent triple-gabled circular building, was once used for emperors to pray for good harvests during the Ming (1368-1644) and Qing (1644-1911) dynasties.