Durro Main Festival Activity · la Vall de Boí, Alta Ribagorça, Lleida Image of la Vall de Boí, not of the place itself. Festa Major de Durro, in the municipality of the Vall de Boí (Alta Ribagorça, Lleida), the heart of the summer-solstice falles. It is celebrated in the first half of June and has its origin in ancestral rites, predating the Indo-European peoples, in which fire was used to ward off evil spirits and give thanks for the harvest. The village's young people cut pine trees to make resinous torches, the falles, with which they descend the mountain alight, forming rivers of fire until they reach the square, where the festival culminates in a communal bonfire and traditional dances. Photo: Enfo (CC BY-SA 3.0) What to see and do in la Vall de Boí