Indents in the pavement are all that remain from a grisly death machine in Paris.

This Irish show cave is said to have been the site of a Viking massacre that claimed 1,000 lives.

World's largest cave was only discovered in 1991, and now offers tours to the public.

The lowest point in North America is home to an undrinkable pool surrounded by fields of geometric salt flats.

The 1936 Summer Olympics site is a crumbling remnant of sportsmanship and a history its host country would like to forget.

The Dalai Lama named this New Zealand landscape the "Spiritual Center of the Universe."

An Italian hillside ghost town.

This natural Icelandic fissure allows divers to swim right between two volatile tectonic plates.

An abandoned NSA listening post on Berlin's "Devil's Mountain."

Found art has transformed this Pittsburgh neighborhood into a psychedelic dream.

An earthwork sculpture built by Robert Smithson in the Great Salt Lake only reemerges during drought.

The yawning maw of this pagan visage is said to bite off the hands of liars.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

"Dark Sky Park" is heaven on Earth for astronomers, one of the rare U.S. locations with no artificial light pollution.

The largest stone moai on Rapa Nui.

Legends surround this jagged rock formation in the New Mexico desert.

A large grotto built in the 16th century amidst Florence's famous Boboli gardens.

A student driver's nightmare.

Natural cathedral designed by Italian artist Giuliano Mauri.

Disney's abandoned animal island is now an overgrown ruin that was almost the coolest attraction ever.

The world of the ancient Celtic civilization explained through a bewitching 11 acre garden.

This impressive tunnel was dug entirely by hand over the course of 36 years.

Remnants of a Victorian garden feature sitting in public woodland.

An extraordinary mixture of natural beauty and man-made phenomena.