The main characteristic of Castellfollit de la Roca is due to the fact that the historic core of the town is located on a base of basalt rock overlooking the valley below.
This natural wall, more than 50 meters high and about a kilometer long, is the result of the erosive action of the Fluvia and Toronell rivers on the volcanic rock which lasted for thousands of years.
The narrow alleys of the town are surmounted by low buildings built with stones and basalt rocks on which stands the Renaissance-style Clock Tower, which can be visited by climbing a spiral staircase, and the ancient church of Sant Salvador, dating back to the 13th century, which represents the symbol of Castellfollit de la Roca.