Special thanks to Todd Fearer for providing the photos for this article.
Tropical rainforests are the most diverse ecosystem on Earth, and also the oldest.
Today, tropical rainforests cover only 6 percent of the Earth's ground surface, but they are home to over half of the planet's plant and animal species. In this completely unique world, there are thousands of species we haven't even discovered yet. In this edition of HowStuffWorks , we'll travel into the tropical rainforest to see what makes it such a bountiful environment for plants and animals. We'll also see why the rainforests are in danger and look at some of the ways this affects us. Inc. All rights reserved.