Xiyang Lou
The Xiyang Lou were commissioned by the Qianlong Emperor and designed mainly by the Italian Jesuit Giuseppe Castiglione who was in his service as a court painter.
Castiglione relied on the French Jesuit scientist Michel Benoist for the engineering tasks, in particular for the fountains, which were the chief interest of the emperor.
Construction was carried out by Chinese craftsmen working under their supervision with some further contributions by other European artists, such as the German Ignaz Sichelbarth and the Florentine Bonaventura Moggi.
Like the rest of the Old Summer Palace, the Xiyang Lou was destroyed in a fire laid by the Anglo-French allied forces in 1860 during the Second Opium War in response to the imprisonment and torture of their peace delegation by the Chinese.
The main structures of the Xiyang Lou are: the Huanghuazhen labyrinth, the Xieqiqu (Harmonious Wonder) waterworks, the Yang Que Long (a gate with aviaries), the Fangwai Guan (belvedere), the Haiyan Tang (Hall of National Peace), the Yuan Ying Guan (Immense Ocean Observatory), the Da Shui Fa (Grand Waterworks), the Guan Shui Fa (Throne for Viewing the Waterworks), and the Xian Fa Shan (Hall of Perspective).
The emperor is said to have sat in this pavilion to watch his concubines competing in a race with yellow lanterns through the labyrinth on the occasion of the Mid-Autumn Festival.
The mansion is said to have been frequented by a Uyghur concubine Consort Rong in favor with the Qianlong Emperor and have contained tablets inscribed in Arabic which were lost in the early 20th century.
The Haiyan Tang (海晏堂, Hall of National Peace) is a building and garden complex erected east of the Fangwai Guan in 1759.
The fountain was known as the "Water Clock" because it was surrounded by twelve bronze waterspouts in the shape of human bodies with animal heads which were successively activated every two hours.
The Yuanying Guan (远瀛观, Immense Ocean Observatory), the Dashuifa waterworks (Chinese: 大水法; pinyin: Dàshuǐfǎ, 40°0′43.45″N 116°18′23.73″E / 40.0120694°N 116.3065917°E / 40.0120694; 116.3065917), and the throne of the Guanshuifa (观水法) are located at the center of the Xiyang Lou complex, where the form a much shorter north–south axis.
