Ten things you never knew about the ocean’s deepest places

The ocean is deep. In fact, most of it is deep. Officially anything deeper than just 200 metres is considered the “deep sea”, but the average depth of the entire ocean is about 3.5km and the deepest point – the Challenger Deep in the Mariana Trench, in the western Pacific – is a little short of 11km down. That means that most of the living space on Earth is in the deep sea.