An ancient stone fortress considered by many to be the eighth wonder of the world.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

Thanks to an acoustic anomaly, this unassuming stone bench has heard one hundred years of secrets.

Three bridges and one giant canyon make up this fantastic Spanish settlement.

This eye-popping Icelandic crater lake is surrounded by red volcanic rock.

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

Possibly the world's largest hourglass only needs to be reset every New Year's Eve.

A mysterious echo seems to defy the laws of acoustics.

An acoustic anomaly with a mysterious cause.

A psychedelic labyrinth on the San Francisco bay.

The effect of this ancient form of image projection situated atop an 11th century Moorish palace is thrilling.

Hidden in the hills is a mysterious stone structure, known only to a few.

A peculiar clock commemorates a historic victory won by ringing the noonday bell an hour early.

Smallest house in Toronto sits on a lot meant to be just wide enough for cars to drive through.

One of the largest underground systems runs under Canada's largest urban center.

A castle built for love, and abandoned due to heartbreak.

The summit Roosevelt conquered before he descended to become The Chief.

The last physical evidence of the Lewis and Clark trail is one of their autographs etched into this giant rock.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

Rome's semi-secret peephole vista is also a former Crusader stronghold.

A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.

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

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

The Pope’s secret escape route.