Fair of la Muntanya de Bossòst Activity · Bossòst, Val d'Aran, Lleida Image of Bossòst, not of the place itself. There is no record of a 'Fira de la Muntanya' in Bossòst; the documented fair of the municipality is a commercial and livestock fira held every 20 October. Photo: Rafael Jiménez from Córdoba, España (CC BY-SA 2.0) What to see and do in Bossòst