Aside from the hills, one of La Garrotxa's most remarkable geological sights is the town of Castellfollit de la Roca (10km northeast of Olot), teetering on the edge of a blackened basalt cliff face made up of two superposed lava flows. The best views are from the road beneath town, near Hostal Mont-Rock.
Castellfollit de la Roca
The Catalan Pyrenees