Yuanmingyuan, which extolled as the "Garden of Gardens", was used to be an imperial summer palace for imperial family. The palace was continuously expanded under five emperors' supervision in the Qing Dynasty, and the expanding went on over 150 years.
It glorious past might have come to an abrupt end as its buildings were destroyed by the British and French armies during the Second Opium War in 1860. Much damage was caused after this by locals using the site as a source of building materials. [China.org.cn]