The largest church in Bielefeld is the Neustädter Marienkirche, a Gothic hall church dating back to 1293, completed 1512. Historically speaking, this building is considered to be the most precious possession of the town. It was the starting point of the Protestant Reformation in Bielefeld in 1553. A valuable wing-altar with 13 pictures, known as the Marienaltar is also kept inside.
The baroque spires were destroyed in World War II and later replaced by two unusually-shaped 'Gothic' clocktowers. The altarpiece of the Bielefeld church Neustädter Marienkirche from around 1400 is among the most prominent masterpieces of artwork of the German Middle Ages. Two of the altarpieces, The Flagellation and The Crucifixion are now in the collection of the Metropolitan Museum of Art in New York.
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.