The Summer Palace (Yiheyuan) in the northwestern suburb of Beijing was built in 1750. by far the best-preserved imperial garden in China , it was endorsed by the UNESCO in 1998 as a world cultural heritage site. As a paragon of Chinese gardens, this huge garden includes Longevity Hill, whose beauty is set off by a multitude of halls, kiosks and trees, and Kunming Lake , a huge body of liquid silver. Major tourist attractions are Tower of Buddhist Incense , 17-Span Bridge, Long Gallery, Cloud Dispelling Hall, Marble Boat, Beamless Hall, Garden of Harmonious Delights , the theatre in the Garden of Moral Harmony , and Suzhou Street . The entire place is a de facto museum of China 's classical architecture. Housed in these buildings are an immense collection of treasures and cultural artifacts.