Sand dunes belch, moan and hum. They roll across the desert, seeking out new locales. You might even say they breed. It's no wonder people call these giant sand formations lifelike. See more »

Like the members of an ill-fated rock group, the seven continents struck out on their own hundreds of millions of years ago. But what caused the breakup? And is a reunion tour in the works? See more »

Wishing you could start your own country? There's good news and bad news. The bad news is that it will take a lot of hard work to make this dream come true. But the good news is that there's actually a procedure in place to make it happen. See more »

Continents aren't the unchanging, universally recognized land masses of our school studies. But they do help us make sense of our world. How did they get their names? See more »

Did you know that sand dunes can sing? And, their artistic curves certainly make for a gorgeous photograph. In fact, you might call the sand dune the diva of the desert. See more »

Much of the ice has melted, and the woolly mammoths are long gone. But could we still be in an ice age and headed for another? See more »

Depending on who you ask, urban sprawl is either the best thing that ever happened to growing families -- or the downfall of civilization and the environment as we know it. Learn about the history and consequences of this American phenomenon. See more »

Some people like to honeymoon at Niagara Falls, while others go over the falls in a barrel. How do these geological formations come to be? See more »

There's no need to do any globetrotting to explore the regions of the Earth and to test your knowledge about the far corners of the world: You can do it with our geography quiz. See more »

Potatoes. Moles. Time capsules. Some things just belong underground and thrive in that dark, airless environment. Humans have long preferred topsoil to the subterranean, but some designers are looking to change that. See more »