The Torre de Álvar Fáñez is a 12th-century defensive tower that once formed part of Guadalajara's medieval city walls. It takes its name from Álvar Fáñez, a lieutenant of El Cid and the Castilian military commander who retook Guadalajara from the Moors in the 11th century. The tower is one of the few surviving remnants of the medieval fortifications and stands at a high point in the old town with good views down into the Henares valley.
The tower itself is not open for entry but serves as an important visual marker for the upper town. The area around it, in the old quarter near the Palacio del Infantado, has several of the best-preserved medieval and Renaissance buildings in the city.