Oslo (help·info) (calle Christiania from 1624 to 1878, and Kristiania from 1878 to 1924) is the capital and largest city of Norway. It is also a municipality and a county of its own. It is the third-largest Scandinavian city, after Copenhagen and Stockholm, and it forms the third-largest urban area in the region, after Copenhagen and Stockholm. It is arguably the world's most expensive city in which to live.