Sera is the second biggest Gelupa Monastery in the north suburb of Lhasa, which was built in 1419 by Tsongapa's disciple Sakya-yeshi. Situated at the heart of the oldest section of the Lhasa city,Jokhang , one of the oldest temples in Tibet, was built in the 7th century by the 33rd king Sontsanganbu. Barkor is the middle pilgrimage circuit around Jokhang temple.)