The plague quarantine island home to the alleged "Vampire of Venice."

A half-mile long and three stories high, this bridge over the Des Moines River Valley mimics a descent into a mine shaft.

This small stone chapel is a hidden gem just outside the University of New Hampshire campus.

At Monet's beloved home you can still see the Japanese bridge, waterlilies, and weeping willows that were the subjects of some of his most iconic paintings.

This ship carrying cargo and four church bells for the Catedral Metropolitana Nossa Senhora Aparecida ran aground in 1968.

Ralph Waldo Emerson spent two years living here decades before it became a Frederick Law Olmsted-designed park.

A hidden art gallery in an abandoned Warsaw fort.

The traditional houses along the coast of this charming Japanese fishing village allow people to sleep above the sea.

Every drop of D.C. tap water flows through this old waterworks.

The water here is so clear you can see the mysteriously sunken ship from the surface.

A fantastical and futuristic temple of light built from nine monumental glass veils.

During the holidays, a vintage subway train whisks New Yorkers back in time.

A hidden tunnel of bones in one of Malta's oldest churches.

A striking 12th-century-style castle built on the edge of a cliff.

This strange, big-tailed beast became a Pennsylvania town's unofficial mascot.

The weathered grave of a medieval anchoress who walled herself up in a cell attached to a church.

A million and a half tons of earth were used to create one of the world's largest land sculptures.

A jungle cave in Peru of unknown depths, otherworldly sounds, and strange nocturnal birds that navigate by echolocation.

A remote hilltop covered in giant monoliths haunts the Brittany countryside.

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

The macabre collection of Jacques Sirgent, an expert scholar on the undead and all of their trappings.

A scenic canyon with thick forests and historic ruins.