Interior at Drepung (Rice Heap) Monastery the largest in Tibet where up to 10.000 monks once resided.  Now only a few hundred remain as their numbers are strictly limited. 

Drepung monastery was closed down by Chinese authorities on March 14th 2008 following monk-led protests against Chinese rule that turned violent. It reopened 5 months later.

Lamps burn to clear the mind and as an aid to meditation.   

Traditionally they burn the so called yak butter.  As yaks are male it is extremely unlikely that this is technically speaking yak butter.