The place we're looking for in our Geo Quiz is deep in the western Pacific Ocean.

How deep is it?

It's so deep that sunlight can't penetrate down to the seafloor, almost seven miles down.

It's so deep that the water pressure is intense. Scientists study this underwater environment with robotic equipment designed to tolerate extreme depths.

Still it's a place that Robert Turnewitsch, an oceanographer at the Scottish Marine Association, would love to see up close:

"I would love to go down there one day and see this fantastic environment with my own eyes and directly and not through a cable and a camera," he says.

So can you name the deepest part of the world's oceans?

Marine scientists have discovered an abundance of tiny, microbial forms of life thriving in one of the most extreme environments on the planet, the Mariana Trench, the deepest place in the world's oceans.

Oceanographer Robert Turnewitsch of the Scottish Association for Marine Science, is a member of an international scientific team whose recent findings are published in the scientific journal Nature Geoscience.

Turnewitsch tells The World that it's important to explore the extremes of the global ocean to help better understand how organisms adapt to a wide range of environmental conditions.

From PRI's The World ©2015 Public Radio International