Like many churches in Friesland, St. Martin's Church was built on a terp, a heightened piece of land to protect whatever was on it from floods. Several churches had been standing on this spot before this one, although the terp had been at least two metres lower when the first church was built. The current church dates from the early 15th century and was named St. Martinus until the Reformation of 1580, when it was conficated for protestant use. Although it also served as a pilgrims church in memory of St. Boniface, who had been murdered nearby in the year 754.
Originally St. Martin was a one-aisled building in Gothic style. The northern side-aisle was added in the late-16th century and has round-topped windows. For the construction of this side-aisle stones were used of the abbey-church that was demolished in 1589 as a result of the Reformation, and that had been standing next to this church. The facade of the original aisle has a stepped gable, a 20th-century reconstruction of an old situation as known from old drawings. At the back, built directly against the choir, is a consistory with a facade dating from 1734.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.