Cardiff is the capital city and one of the principal areas of Wales. It is Wales' largest city and the eleventh-largest city in the United Kingdom. Cardiff is the county town of the historic county of Glamorgan and in 1974–1996 of South Glamorgan. It belongs to the Eurocities network of the largest European cities. A small town until the early 19th century, its prominence as a port for coal when mining began in the region helped its expansion. In 1905 it was ranked as a city and in 1955 proclaimed capital of Wales. Cardiff Built-up Area covers a larger area outside the county boundary, including the towns of Dinas Powys and Penarth.
Cardiff is the main commercial centre of Wales as well as the base for the Senedd. At the 2011 census, the unitary authority area population was put at 346,090, and the wider urban area at 479,000. In 2011 it ranked sixth in the world in a National Geographic magazine list of alternative tourist destinations. It is the most popular destination in Wales with 21.3 million visitors in 2017.
Cardiff Bay contains the Senedd building and the Wales Millennium Centre arts complex.