Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

Commonly acknowledged as the only public monument to the Devil himself.

Over two centuries old and counting, Madrid's massive botanical garden contains one of Europe's only desert environments.

In the fictional world of Kcymaerxthaere, celestial wonders marked a portal to a powerful route of travel at this site in Madrid, Spain.

The remnants of two World's Fairs are here, complete with a 12-story globe, a mini-Manhattan, and a UFO-shaped pavilion.

A museum devoted to bringing to light forgotten or neglected histories through exhibitions, education and public programming.

The haunting, dilapidated remains of a former poorhouse on Staten Island's Greenbelt.

This sculpture by artist Fritz Keonig survived the 9/11 attacks and now stands as a monument to the victims.

A museum collection honoring the long history of the FDNY is held in a disused Manhattan fire house.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

Elevated freight railway turned wildly successful urban park.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

Discovered by cows, these upstate New York show caves are presented with a healthy dose of psychedelic folk art.

Decades after testing the polio vaccine on unwitting patients, this historic mental hospital sits in ruin.

Collapsing castle on the Hudson river was once the storage site of military surplus business.

Why have you never heard of the second most popular tourist site in New York?

A private museum dedicated to preserving the heritage of Mardi Gras' most beloved underdog parades, open by appointment.

In 2010, Nicolas Cage purchased two plots in this cemetery using one to construct this strange pyramid mausoleum.

This "second" cemetery represents New Orleans' attempt to keep cholera at bay.

New Orleans' famous cemetery, located on the site of a former race track.

The "Fun Spot of the Desert" is now a haunting ruin, and a reminder that putting a water park in a desert is a bad idea.

Hundreds of trees made from glass bottles make up this forest on Route 66.

The ghost town that ended up on Ebay.