Fly through the Mariana Trench

Four teams are diving to the deepest part of the ocean, the Mariana Trench, which lies 11km down in the western Pacific.

But while adventurers are looking to roll back this final frontier, scientists are also realising the potential of the deep.

Here, Jim Gardner, from the US Center for Coastal and Ocean Mapping, explains how he has created the most extensive map of the Mariana Trench to date, and has been able to get a measurement of its deepest part: the Challenger Deep.