London is one of the most powerful cities on Earth, but how did this area, once the undisputed capital of the English-speaking world, become so dominant?

London is one of the most powerful cities on Earth, but how did this area, once the undisputed capital of the English-speaking world, become so dominant? Through a series of astonishing maritime discoveries, the Thames' water is drained, revealing fresh evidence of how the centre of a once huge empire became so dominant.