London is the capital of the United Kingdom. It is by far the largest city in the British Isles, and the largest city in Europe. It was probably the largest city in the world from the late 18th century to World War II.
London was founded by the Romans, who called it Londinium and built the first bridge across the Thames there. It was not the original capital of the Roman province, but became the capital after Boadicea's destruction of Colchester.
London is bisected by the River Thames.