Getting under Antarctica’s ice is no small feat. According to the National Science Foundation, the ice has a depth of 4,776 meters and an average thickness of 2,160 meters. In total, Antarctica contains 27 million cubic kilometers of frozen water, the melting of which would result in an increase of about 58 meters in sea level.

Researchers have drilled holes more than 2,000 meters deep in the Antarctic ice, but most of the lower depths remain a mystery. They’ve also placed cameras in some shallow boreholes, providing incredible surveillance.

Arctic ice is not that deep. Even in large areas, its thickness can be only 3-4 meters, and the depth of the ridges can reach 20 meters. Below are the waters of the Arctic Ocean, the shallowest of the world’s five great oceans, with an average depth of just 1,038 meters.

If you want to dig deeper into the question of what’s under the Arctic ice sheet, we have to go to the bottom of the Arctic Ocean.

In 2013, scientists from Columbia University’s Lamont-Dougherty Earth Observatory spent a lot of time researching and gathering information about the world beneath the Arctic ice in Barrow, Alaska. They pointed cameras through the ice into the waters of the Arctic Ocean and collected video images of the seafloor.