The Potala Palace, where construction began during the 7th century A.D. by Emperor Songtsen Gampo, was built upon in the 17th Century during the time of the 5th Dalai Lama. It was built as the home of the Dalai Lama and used to serve as the seat of the Tibetan government and a training place for monks and others. It is truly a site to behold. So much so that i've included three photos plus a view from on top! :-)