I have always been fascinated by Marianas trench which is the deepest place on Earth.  It is 200 kilometres to the east of the Mariana Islands in the Pacific Ocean close to the Philippines.  It is 10,000 metres deep which is much deeper than the Earth’s deepest canyon which is the Cotohuasi Canyon in Peru.  If you had to drop Mount Everest in Marinas Trench there would be more than a kilometre of space left to go to the surface.

Here is a great video of James Cameron in the Marianas Trench and also a really interesting diagram which shows just how deep it really is.