Did you know that while the earth looks like a marble in space, the earth isn't a perfect sphere? Did you know that while all human life is found on land, the ocean makes up 71 percent of the planet? Not only that, but most of the world's oceans have yet to be explored! Discover planet earth, from its highest mountain peaks to the lowest trenches in the ocean. Through this book's unique formatting, readers will learn amazing facts about earth and then find out how we know each fact.