This abandoned amusement park was built on a site with a dark history.

A colossal sculptural lion built by the same man who designed the Statue of Liberty.

A Texas-sized particle collider that was abandoned due to its Texas-sized budget.

This expansive bridge in the Canadian wilderness was originally just built for friends.

Venice's "Island of the Mad."

A stunning bridge that appears as if it's lunging to the shore, and has a legend of a devilish architect.

A hollow cement depiction of time's inexorable effect on the human body.

A sacred well steeped in Pagan roots on the West Coast of Ireland.

A lone pole once used to display a man's corpse now stands empty, but the memory remains.

A crumbling cathedral condemned by an earthquake.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

This former fascist summer camp was abandoned for decades.

A museum dedicated to the history of a terrifying secret police is now held in their former headquarters.

This disused VLF radio station is no longer in service but the surrounding town still bears its name.

The longest continuous lava tube in the continental U.S. offers 2.5 miles of dark explorations for the adventurous.

The site of one of the strangest disasters in history—a wave of deadly molasses traveling at 35 mph.

A Pythagorean funhouse that tries, successfully, to prove that math is the coolest thing ever.

Mysterious hillside with a continuously burning natural fire.

This Italian-style temple replica has been threatening to fall off the Irish coast for hundreds of years.

The alleged house of the Virgin Mary is tucked away in a park and nature preserve on Mt. Koressos in Turkey and is holy to both Catholics and Muslims alike.

The old Niles Canyon Aqueduct in the San Francisco Bay Area is a bemusing and secret trail through nature for wayward travelers.

Nondescript elevator doors open to reveal a stunning, surreal world.

Leveled by an earthquake, this Italian village is now preserved as a massive concrete art project.

The odd cement nubs littering this Spanish square are actually the entrances to a series of buried silos.