South of Luchon, on the road to Superbagnères.
In the medieval period, many isolated square towers were built on the slopes of the Pyrenees. They were watchtowers or signal towers for guarding important routes and their positions relative to each other suggest that they also communicated by signal. In times of upheaval they could house a small garrison. The tower of Castel Vielh is on four levels, the top floor having a masonry-work barrel vault roof supporting the watcher’s platform at the top.