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

The first declared National Monument in the United States.

Stepping away from the glitz of mobsters and casinos to learn about the other history of Vegas.

A beautiful 62-acre Catholic shrine and botanical garden.

The ghostly remains of an accidental sea.

The world's largest collection of witchcraft regalia.

This weird abode has inspired everything from the "House On Haunted Hil" to a robot hunter's pad.

Philadelphia boasts one of the best — and most often overlooked — traditional Japanese gardens in North America.

The remains of a failed attempt at medieval nerdery are hidden deep in the woods of Virginia.

A museum of carnival attractions where you are invited to ride the rides.

The land is full of geologic eye candy, such as otherworldly spires, mushroom-shaped hoodoos, and prehistoric fossils.

A museum dedicated to the history and exploration of both popular music and science fiction.

Hollywood's most famous landmark, the "temporary" sign that has stood for decades longer than intended.

This New Orleans tree is filled with hidden chimes that produce a carefully tuned melody.

The rocks in this arid basin leave trails of movement behind them.

The deepest lake in the United States, and once the site of epic destruction that lives on in legends.

Mysterious rocks that ring musically when struck.

This charming cobbled backstreet is the most Instagramable street in Paris, much to the residents' annoyance.

Winding paths and ramshackle mausoleums in the oldest "park cemetery" in London.

Hidden beneath the streets of London is a secret subway that only carried mail.

Started as a kitchen garden, now the second largest botanical garden in the world.

17th century streets hidden under Edinburgh were once a breeding ground for the black death.

Get lost in this haunting fairytale art walk through a man-made eucalyptus grove.

Two stunning 17th-century libraries and a cabinet of curiosities.