Image: Devils Tower Climbers

Rock climbers high on Devils Tower, northeast Wyoming, USA. Formed by magma that hardened beneath the earth's surface 50 million years ago, then appeared above the landscape 1-2 million years ago as the softer rock around it eroded away, this otherworldly formation is sacred to local Native American tribes. According to legend, the Great Spirit made the rock rise out of the earth to help people escape a giant bear, who angrily clawed at the sides as it grew.