It's been under water for almost two centuries, but today visitors to one of north London's locks got a rare chance - to take a tour inside.
Camden Lock has been drained for restoration work, exposing the structure of the chamber.
It'll cost 130 thousand pounds to replace both sets of gates and repair the timber work.
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Pictures of today's events unfolding following a major security incident at the Houses of Parliament.
At least two people have died after a knifeman brought terror to the heart of Westminster.
The Cobra committee brings together government ministers with senior officials of the emergency services and security agencies.