Avatar director James Cameron is preparing for an attempt to be first human being in 50 years to visit the deepest point on Earth – the bottom of the Mariana Trench, seven miles down in the Pacific.

The director will start his attempt ‘within weeks’ – becoming the first of at least four teams racing to the ocean floor, an icy, alien environment with pressures 1,000 times higher than the surface.

Many liken the journey to man’s steps into space. ‘The deep trenches are the last unexplored frontier on our planet,’ says Cameron.