Puente de San Martín bridge was constructed in the late 14th century by archbishop Pedro Tenorio to provide access to the old town from the west, complementing the older Puente de Alcántara linking to the east. Both sides of the bridge were heavily fortified with towers, the more recent dating from the 16th century.
The Puente de San Martín features five arches, with the largest in the middle reaching an impressive span length of 40 m. Only very few bridges in the world had reached that mark until then.References:
The city walls of Avila were built in the 11th century to protect the citizens from the Moors. They have been well maintained throughout the centuries and are now a major tourist attraction as well as a UNESCO World Heritage Site. Visitors can walk around about half of the length of the walls.
The layout of the city is an even quadrilateral with a perimeter of 2,516 m. Its walls, which consist in part of stones already used in earlier constructions, have an average thickness of 3 m. Access to the city is afforded by nine gates of different periods; twin 20 m high towers, linked by a semi-circular arch, flank the oldest ones, Puerta de San Vicente and Puerta del Alcázar.