"Portugal's Stonehenge" is made up of nut-like stones aligned with the heavens.

This ancient hydrological marvel is now the base of a modern outdoor cinema.

The Earth's saltiest natural body of water belches toxic gas.

Ethiopia's "smoking mountain" is in one of the hottest regions on the planet and is home to two lava lakes.

Reaching the "Church in the Sky" requires scaling the cliff face of a sandstone pinnacle with a 650-foot drop.

The hottest place on the planet.

An Ethiopian "Jerusalem" featuring a church hewn out of a single rock.

Half-sized replica of the Leaning Tower of Pisa built to honor Galileo.

Rock-cut caves and 7,000 Buddhist sculptures carved into the nearly sheer face of a sandstone mountain.

Mussolini gave Cincinnati a bronze statue of Romulus and Remus suckling at a wolf's teats.

Cretean quarry suggests real-life site for ancient Greek myth of the man-eating Minotaur in his labyrinth.

A salty red wasteland in Tanzania is a breeding spot for endangered flamingos.

Apartment complexes built into huge repurposed natural gas tanks.

An endless sea of white conical domes.

A collection of massive stacked rocks in Texas includes a snarky note on the benefits of modern technology.

Italian cave with exceptional acoustics and an unsavory history.

Monument to a suicide protesting the Soviet invasion.

The Twisted Trees of Alticane are an unnerving grove of Quaking Aspen, apparently mutated from a single source, giving them a twisted and unnatural appearance.

These quaint French houses dangle precariously over a precipice.

Alabama has a fiberglass Stonehenge. With apologies to Spinal Tap, this one is full-size.

A six-story-tall golden pyramid, surrounded by a moat.

An eerie and beautiful group of columns mark the site of a grand mansion lost to time and fire.

A local scoured more than 1,000 acres for stone to create his masterpiece.

This stunning mass of ice spans 121 square miles and is still growing.