It is the head monastery of the Drigungpa school of the Kagyupa order. It was first establishedd in 1167. Right now there are 270 monks at Drigung Til.
The monastery kora heads up the hill to the main durtro. This is the holiest sky-burial site in the Lhasa region- people travel hundreds of kilometres to bring their deceased relatives here. Sometimes it's possible to observe a sky burial, but it is absolutely essential that you gain permission from both the family of the deceased and the senior lama who conducts the ceremony.