Only about 20% of the ocean’s depths has been mapped by humans. Here’s what we do — and don’t — know about the deep seas and why studying them is so risky.

It would take nearly 300 years — in the aftermath of the Titanic disaster — before sonar technology began to offer scientists a clearer picture of what lies in the ocean's depths.A major step ...

Over the past two decades, more than one-fifth of the world's oceans, an area exceeding 75 million square kilometers, have ...

The deepest regions of Earth’s oceans, known as the abyssal and hadal zones, lie at least as far under the water’s surface as Mount Rainier’s peak rises above the land surface. These great depths of 4 ...

Satellite data has enabled researchers at the U.S. Geological Survey (USGS) to develop a new way to measure ocean depth. The technique, which uses imagery captured by the Landsat program, works ...

A history of ocean exploration. The first submarine was built by Dutch engineer Cornelis Drebbel in 1620, but it stuck to shallow waters. It would take nearly 300 years — in the aftermath of the ...

It would take nearly 300 years — in the aftermath of the Titanic disaster — before sonar technology began to offer scientists a clearer picture of what lies in the ocean's depths.A major step ...

It would take nearly 300 years — in the aftermath of the Titanic disaster — before sonar technology began to offer scientists a clearer picture of what lies in the ocean's depths.A major step ...

It would take nearly 300 years — in the aftermath of the Titanic disaster — before sonar technology began to offer scientists a clearer picture of what lies in the ocean's depths.A major step ...