Potala Palace - fortress, Tibet

The Potala Palace is a dzong fortress in Lhasa, Tibet. It was the winter palace of the Dalai Lamas from 1649 to 1959, has been a museum since then, and a World Heritage Site since 1994. The palace is named after Mount Potalaka, the mythical abode of the bodhisattva Avalokiteśvara.[1] The 5th Dalai Lama started its construction in 1645[2] after one of his spiritual advisers, Konchog Chophel (died 1646), pointed out that the site was ideal as a seat of government, situated as it is between Drepung and Sera monasteries and the old city of Lhasa.[3] It may overlay the remains of an earlier fortress called the White or Red Palace on the site,[4] built by Songtsen Gampo in 637.[5] The building measures 400 metres (1,300 ft) east-west and 350 metres (1,150 ft) north-south, with sloping stone walls averaging 3 metres (9.8 ft) thick, and 5 metres (16 ft) thick at the base, and with copper poured into the foundations to help proof it against earthquakes.[6] Thirteen storeys of buildings... Wikipedia.org