The 19th century's dream of an open polar sea has become the 21st century's nightmare.

For the first time in 50 million years, we now have an open polar sea.

Scaling its sides, they eventually found a passage through to the polar sea.

They scale the waterfall at the end of the river and make their way, after much difficulty, to the polar sea.

She had been built tough to tolerate massive polar seas.

The view reminded scientists of pack ice on a polar sea.

The polar seas play an important role in the global climate:

No land, that is, just ice drifting over the polar sea.

Her eyes were large, gray as a polar sea, and seemed to hold all the knowledge of the world.

The contrast to the ordinary aspect of polar seas was very remarkable.