Ruins of the European-style palaces at the Old Summer Palace, 8 km (5 mi) northwest of the Imperial City section of Beijing. The complex of palaces and gardens was originally referred to as the Imperial Gardens. Constructed throughout the 18th and early 19th centuries, the Old Summer Palace was the main imperial residence of the emperor and where he handled state affairs; the Forbidden City was used for formal ceremonies. Widely perceived as the pinnacle of Chinese imperial garden and palace design, the Old Summer Palace was known for its extensive collection of gardens, its building architecture, and numerous art and historical treasures. Referred to as a “Garden of Gardens,” it was destroyed in 1860, during the Second Opium War.