Drepung, eight kilometres west of central Lhasa, was once the largest monastery in the world. Its name means "rice heap", and from a distance the cluster of whitewashed halls spilling down the lower flank of Mount Gephel does look like a pile of grain. Founded in 1416, it became one of the three great Gelugpa monasteries of central Tibet, alongside Sera and Ganden.
Walking up through the maze of stone alleys feels like entering a small town. The Tsogchen, the main assembly hall, is the showpiece — vast, low-ceilinged, packed with butter lamps and the lingering smell of fermented barley. The four colleges (tratsangs) each have their own assembly halls and shrines, and the climb between them is itself a pilgrimage, with kora paths winding up to a viewpoint over the Kyichu valley.
The Shoton Festival, held here on the first day of the seventh Tibetan month (usually August), brings the unveiling of a giant thangka on the hillside above the monastery and crowds of pilgrims, monks and Lhasa families with picnics. If you can time a visit, do.