Over millions of years, this limestone formation created a massive reef structure that stretched across hundreds of miles.

Beneath the towering Guadalupe Mountains of Texas lies a dramatic story of transformation. Once part of an ancient sea, the fossilized Capitan Reef now forms craggy peaks and iconic cliffs like El ...

The most popular U.S. National Parks are packed with people. To avoid crowds, consider visiting one of these 10 less crowded, ...