London's river and its secrets

LONDON (Reuters) - London's River Thames has been the lifeblood of the British capital since the city's origins as a Roman garrison town around 2,000 years ago. The artery through which the world's trade passed at the height of the British Empire, its banks were lined with factories that drove the industrial revolution but left its waters biologically dead. Now, with power stations transformed into galleries, the river is home to seals, the occasional porpoise and has become a much-loved open sp