Oslo is the capital city of Norway, and has a population of approximately 538,500 people. About 22 percent of the population are immigrants. The city is divided into 15 boroughs that are mostly self governed. In addition, there is the main city center and the rural/recreational areas that don't have an administration of their own. According to The Economist, Oslo is ...the most expensive city in the world.... The city of Oslo was once referred to as The City of Tigers by author Bjornstjerne Bjornson around 1870. At the 1,000 year jubilee, a row of tiger sculptures were placed around City Hall. Tourist attractions in Oslo include the Akershus Castle and Fortress, the Norsk Folkemuseum (including the open air museum), the Armed Forces Museum, City Hall (where the Nobel Peace Prize ceremony is held), a Historical Museum, and the Holmenkollen Winter Olympic site(s). In addition to other sites within Oslo, there are scores of others close by. There are eight colleges or universities in Oslo. Oslo was the host city for the 1952 Winter Olympic Games; except for the downhill skiing at Norefjell, all events took place in the city.