See massive fossils that are over 200 million years old in northeastern Arizona.

This "dead marsh" sits among the largest sand dunes in the world, a forest frozen in time.

A seemingly endless landscape of pure salt stretches far across Bolivia.

Earth's greatest purely vertical drop at 4,101 feet.

The sign at the garden gate reads: "These Plants Can Kill."

In the middle of an extremely unforgiving and desolate high desert is the most secret military facility in the world.

This giant boulder is pinched over a 1000-meter abyss by two mountains.

This "preacher's pulpit" once used for pagan ritual, is home to a new, and dangerous ritual.

An ancient capital city that dates back 3,000 years old and harbors many surprises.

Named after the Goddess of Harvests, Annapurna is the deadliest member of the Eight-thousanders club.

Keshwa chaca, among the last handwoven Incan bridges, crosses Apurimac Canyon in Peru.

A harrowing trail up a mile-high mountain.

Spanning the El Chorro gorge, this pathway used to be one of the most dangerous crossings in the world.

Natural stone arches form a walkable "cathedral" at low tide, then disappear entirely when the water returns.

A nude beach alongside a washed-out road.

Rocky Atlantic beach home to a stunning stone arch.

An historic and oft-filmed spot for musclebound iron pumpers on the Pacific coast.

Known for the tunnel that leads visitors to the water.

An emerald-green grotto just a short trip from Austin.

A fiery crater has been burning in the Karakum Desert since 1971.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

A lovers' beach, tucked below the surface of the island, provides a safe haven for romance.

America's smallest "national forest" has only 33 trees.

Dramatic river bend surrounds a natural red-rocked pedestal.