Only recently have we come to understand the importance of these ice caps, which act as giant reflectors, bouncing the sun's heating rays back into space and helping keep the Earth cool. As they melt, revealing less-reflective ocean water and land, the earth absorbs more sunlight and grows hotter, hastening even more melting.
But beyond their importance to the globe, these huge ice fields are also astonishingly beautiful and incomprehensibly vast — a natural wonder on a biblical scale. But they are vastly different. The north pole has no land. The "ice cap" actually is an ever-moving sheet of ice hundreds of miles wide that floats on the Arctic Ocean. Home to roaming polar bears, seals and birds, it's just a few feet thick in places.
The south pole, by contrast, is occupied by a massive continent, Antarctica. Bigger than Europe, the "Frozen Continent" is almost completely covered by a giant field of ice that in some places is more than 10,000 feet thick. Containing 90% of the world's fresh water, it's home to grand, glacier-covered mountains, iceberg-laden bays and — during the brief Antarctic summer — teeming wildlife that includes penguins, seals and whales.