Fantastic Pit at Ellison's Cave, Georgia Ellison's Cave far under Pigeon Mountain in northwest Georgia. The cave's "Fantastic Pit," seen here, is the deepest cave drop in the continental United States at a staggering 586 vertical feet vertical meters).
A rare total cloud inversion is pictured at Mather Point on the South Rim of Grand Canyon National Park in Arizona on Nov. Cloud inversions are formed through the interaction of warm and cold air masses.—Erin Whittaker / National Parks Service via Reuters
Outdoor Adventures: 6 Ways to Nurture Your Bond With Nature
The Vredefort Dome is believed to be the oldest and largest clearly visible meteor impact structure in the world. It is located in South Africa, approx 100 km SW of Johannesburg . It is approx 190 kilometers across and is thought to have formed about ago