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

Monuments don't get much more metal than these three giant viking swords planted in a Nordic hill.

Shipwrecks, ruins, and turtles are all that remain on this haunting Caribbean ghost island.

The ruins of this gorgeous clifftop castle look like something from a fantasy novel.

The remote outlaw hideout of Jesse James, Butch Cassidy, and the Sundance Kid.

These steeply terraced ruins are a stop along the Inca Trail to Machu Picchu.

The stones of this Incan wall complex fit together so well you couldn't fit a piece of paper between some of them.

A collision of human error and natural geothermal pressure created this rainbow-colored geologic wonder.

This Sumatran root bridge took almost 30 years to knit itself together.

A total of 999 stairs lead visitors through a massive hole in a mountain known as the Gateway to Heaven.

A fantastical group of cliffside stairways, bridges, and twisting paths carved out of stone provide a surreal coastal hike.

A trio of giant wooden megaphones turn up nature's volume in this Estonian forest.

A graceful natural rock formation stands astride the point where the Gulf of California meets the Pacific Ocean.

One of the largest caverns in the world has a maw large enough to stack cathedrals in.

Thousands of narrow alleyways in an ancient medieval city make up what's believed to be the world's largest car-free urban zone.

One of the most spectacular canyons in the world.

Founded as a refugee camp, now a popular tourist spot.

The world's largest bioluminescent area was undiscovered by science until 2005.

Virgil's many-mouthed gateway to the underworld.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

Japanese national treasure originally built in 593 CE.

This massive mushroom has spent centuries eating its way across a huge swath of Oregon.

Inspired by "The Starry Night" this Dutch bike path turns into a glowing work of art each night.

The "original web site," this farm in Northern Vermont encourages orb-weaver spiders to build their daily webs, and then sells the preserved masterpieces.