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.
You may think there aren't many parts of London that Google hasn't put on the map. But the company is taking things a big step forward, by going in search of the capital's more hard to reach places.
It's using a futuristic-looking bit of kit, to open up some of our historic waterways to the world. Funmi Olutoye has been taking a look at how it works.
Two hundred years ago this weekend, work started on cutting the Regent's Canal in north London.
It took eight years to build, and was vital in moving goods across the capital.
Toby Sadler took to the water to find out more: