St. Hallvard's Cathedral (Hallvardskatedralen), the former Oslo Cathedral, was the earliest cathedral in Oslo. The cathedral was built at the height of the Old Town market square Oslo during the early 12th century, and was used as a church until about 1655. Besides being the bishop's seat and religious center of eastern Norway for about 500 years, the cathedral was the coronation church, royal wedding church, chapel royal, and one of Scandinavia's most visited place of pilgrimage. St. Hallvard cemetery is located mainly south of the cathedral. It was the honorary cemetery in Oslo and eastern Norway from around 1130 to 1639. Here the bishops, chiefs and other prominent men and women were buried. The most prominent was interred in the church along with the kings.
Today the cathedral is in ruins. The main body in the ruins park (Memorial Park), the southern part under a concrete cap - and the concrete lid of the street of Bispegata. Towards the end of the 19th century were Bispegata extended in an easterly direction, over the cathedral site. It has been put in place to remove Bispegata's eastern part, as a result of the completion of the Ekeberg Tunnel and the modified veian resort in the lower Lodalen. In that case, the ruins of St. Hallvard Cemetery exposed, and the Medieval city triangular marketplace, Oslo squares, re-established west of St. Hallvard Cemetery. Neighboring the Cathedral was the smaller Church of the Cross.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.