The Trou de Bozouls is a horseshoe shaped gorge, 400 m in diameter and more than 100 m deep, located on the territory of the commune of Bozouls, in Aveyron, France. This encircled meander has been dug by the erosive action of the current waters of Dourdou in the secondary limestones of Causse Comtal. The unique geography of the area came about 2 million years ago when glaciers advanced and receded. Humans have built settlements in the area for thousands of years, using the limestone rock to create their dwellings.
Photo credit: Mairie-bozouls/Wikimedia