An eccentric garden of sculptures crafted in India decorate an Irish green space dedicated to Alan Turing.

The ruins of a world-renowned medieval hospital.

A Bohemian "anti-hotel" offers off-kilter stays in Sri Lanka.

Once the "Eighth Wonder of the World," this iron railroad bridge was decimated by a tornado.

This small museum houses rare airplanes from aviation's golden age.

The Grand Canyon’s original airport, which once welcomed pilots like Amelia Earhart and Charles Lindbergh, lies abandoned.

Water of undetermined depth has attracted rare fish and cult leaders alike.

This taberna has been frying up crunchy salt cod since 1860.

Mother Nature outdoes herself with this stunningly beautiful set of caves carved into marble.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

The hidden "ballroom" under a mansion lake was built by a criminal who ate a cyanide pill during his trial.

The last remnants of a massive medieval wall that once encompassed the city of Berlin.

This cannonball embedded in the side of an Edinburgh house once served a surprisingly pedestrian purpose.

According to legend, this tomb holds the secrets to time travel.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

Discovered after draining a local pond, these ancient man-made caves are still a complete mystery.

This ancient Roman prison is decorated with an upside-down cross not as blasphemy but as saintly tribute.

Built to celebrate the glory of a new queen, this forgotten monument has moved around Madrid three times, reflecting 200 years of political whims and city redevelopment.

The plunge pool is a surviving relic of a rowdy royal residence.

Thanks to modern navigational tools we now know that the true prime meridian runs through a park next door.

The Ranger’s House exhibits fine mementos collected by Sir Julius Werner during the course of his life, including this infamous pendant.

The handiwork of a underdog clockmaker who solved an impossible problem for an Empire, and forever revolutionized seafaring.

This public observatory is home to the "celestial cannon," the longest pointable telescope in the world.

This monumental work of art symbolizes the coming together of a previously divided city.