With Norway's conversion to Christianity some 1,000 years ago, churches were built. Stonework architecture was introduced from Europe for the most important structures, beginning with the construction of Nidaros Cathedral in Trondheim. In the early Middle Ages, wooden stave churches were constructed throughout Norway. Some of them have survived; they represent Norway's most unusual contribution to architectural history. A fine example, Urnes Stave Church in inner Sognefjord, is on UNESCO's World Heritage List. Another notable example of wooden architecture is the buildings at Bryggen Wharf in Bergen, also on the list for World Cultural Heritage sites, consisting of a row of tall, narrow wooden structures along the quayside.