Conditions
In shallow water it isn’t very compressed, but in deep water it is so compressed it is like having ten elephants on your back.
The deeper you go the darker it gets, because the water above absorbs the light of the sun.
Also the deeper you go the colder it gets until you get to a certain depth where it stays the same cold temperature.

How to get there
To get there you might think is impossible but we have learned how to do it. The machine that is helping us to do it is called a submarine. A submarine is a big tank of air that protects humans from the water but if you want to go really deep you use a very strong submarine called a bathysphere.

James Cameron is a film director who recently went to the bottom of the Mariana Trench in a mini sub.

Animals
Some animals in the deep sea are very strange, for example the Anglerfish has a light on its head to attract prey. There are more than just the Anglerfish, like the gulper eel and the Dragonfish .
All these strange creatures have evolved to the deep sea so well they couldn’t survive in shallow water.