Boí, occupying an intermediary position between Caldes, Erill la Vall, and Taüll.

Medieval. Houses and cobbled streets.

Another curiosity is the name of the "Plaça del Treio," related to the Latin term "Trivium," meaning "three roads," suggesting that Boí was an important crossroads even during the Roman era. The castle, the walls, and the Romanesque Church of Sant Joan bear witness to the village's significance during the medieval period. Also noteworthy is the medieval bridge over the Sant Martí river.

Currently, Boí serves as the starting point to access the only national park in Catalonia, the Aigüestortes i Estany de Sant Maurici National Park, and the location of the Park House. The Church of Sant Joan, declared a World Heritage Site, preserves more architectural elements from the earliest construction period in the valley, dating back to the 11th century. The ensemble of murals found on the exterior and interior walls, featuring scenes such as the stoning of Saint Stephen, jesters, and bestiary, is particularly outstanding. These murals have been reproduced inside the church.