The most highly detailed maps ever released of the Earth's polar regions shows a mysterious world of hidden mountains, canyons and ocean topography underneath the frozen regions' ice caps.

The maps in the newest version of the Times Comprehensive Atlas of the World published in London reveal features hidden by ice sheets in the Antarctic and Arctic.

Where previous maps had been content to display the regions as near-blank expanses of pure whiteness, the Times atlas, based on new surveys, has revealed what's beneath the ice.

It also offers dramatic proof of the extensive waning in the extent of Arctic sea ice as global warming has affected the area in recent decades.

If the ice at the poles were to disappear entirely, what would be revealed would be land looking almost normal, says the British Anatarctic Survey's Peter Fretwell, who led the compiling of the dataset for the Antarctic.

"If the ice was taken away we would have continental features like mountains and canyons, which we don't expect from regions like Antarctica," he says.

Some unique geographical features lurking beneath the ice get their first-time debut in the new atlas.

There's Antarctica's Gamburtsev Subglacial Mountains, as extensive as the Alps and completely buried in ice.

Also in Antarctica is Lake Vostok, locked for millions of years below more than 2 miles of ice.

And the frozen continent is also home to the Astrolabe Trench, filled with the thickest ice anywhere on the globe.

And in the north there's the "Grand Canyon of Greenland," a giant canyon 466 miles long and 2,600 feet deep that is bigger than American's Grand Canyon.

The huge chasm, thought to be older than the ice sheet covering it, was only detected in 2013 and has not yet been officially named.

Data for the new atlas maps was gathered mainly using a method called radio-echo sounding, in which a plane flying over the region to be mapped fires radio waves at the surface below and measures the amount reflected.

Knowledge of what lies beneath the ice is vital because it will constitute a key element in computer models used to predict possible future rises in sea levels, Fretwell says.

"As the world warms with increasing greenhouse gas emissions Antarctic ice will start to melt and cause global sea levels to rise," he explained. "But the speed and amount of sea level rise is very dependent upon the bed-topography under the ice sheet."

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