We've Mapped the Whole Ocean Floor

Only four people have visited the challenger deep, the deepest location on earth. It's at ten thousand 928 meters and about one thousand 100 atmospheres of pressure. No animal, no mammal, can dive that deep. So far we've only managed to actually map about 20 % of the ocean floor. This is a long, laborious process with ships going across every bit of ocean. And the ocean floor is huge - it's massive. But you all agree with the first one. Till we'll start there.