Follow in the footsteps of the world's most famous explorers and travel to the extremes of our environment on Earth--learn about the highest and deepest, hottest and coldest places on Earth. Discover the world's most wild terrain--deserts, mountains, volcanoes, rivers, jungles, oceans, the polar regions and more and learn about how they were discovered and explored by human adventurers. Find out how these regions are under threat from global warming and other issues, and learn what we can do to conserve them.