Martinskirche was built by Franciscan monks during 1226. It is located in Old Town and functions as an important Roman Catholic parish church of the city. The original Romanesque character of the structure was destroyed over time due to several repairs and restoration projects. Today, the church is a center for the ecumenical movement. Fascinating interiors of the church feature a flat wooden ceiling, 14th-century paintings, impressive choir windows from 1919 and the beautiful high altar.