London is the largest urban area and capital city of the United Kingdom. Greater London covered an area of 1,579 square kilometres (610 sq mi), an area which had a population of 7,172,036 in 2001 and a population density of 4,542 people per square kilometre. A larger area, referred to as the London Metropolitan Region or the London Metropolitan Agglomeration covered an area of 8,382 square kilometres (3,236 sq mi) had a population of 12,653,500 and a population density of 1,510 people per square kilometre.... Wikipedia