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

Mysterious 500-year-old tapestries depict a unicorn hunt.

The site of a tragic massacre that spawned a multimedia franchise.

Oldest existing church in New York and the inspiration for Washington Irving's "The Legend of Sleepy Hollow."

Glacial erratic or man-made dolmen? It probably wasn't druids.

An abandoned Gold Coast-era mansion once intended for the exiled ruler of Albania, who never arrived.

Spies, love letters, and ghost stories have all left their mark on this home-cum-museum.

A museum designed by and dedicated to P.T. Barnum in the town where he is buried.

An eccentric playboy's astounding natural history collection.

Beneath the mossy overgrowth covering this once-sprawling campus lies decades of history and the secrets that come with it.

An unrealized dream to wirelessly electrify the entire Earth.

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

Outsider art meets paleontology at this roadside reptile repository.

Quite simply the largest tree in the world (by volume).

Staircase winds down the side of Telegraph Hill through gardens, wild parrots flying overhead.

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

Relics of the 1894 Midwinter Exposition continue to delight visitors today.

A celebration of capitalism in Midtown.

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

The ghost town that ended up on Ebay.

This cemetery has graves dating back to the 17th century, including the city's oldest carved tombstone and an ominous cryptogram.

A collection of 20th-century automata, penny arcade games, and musical contraptions.

The "world's biggest dinosaur" once housed a creationist museum in its abdomen.

The bizarre visions of H.R. Giger, tucked away in a Swiss medieval city.