The one-time watch house for incoming ships at the Golden Gate now stands abandoned and hidden in trees.

Hidden amid the tropical forest in the Caribbean Sea are the decaying ruins of the Cocaine King's luxurious island party home.

A late sculptor's last project was to turn this abandoned cement factory into a castle-themed amusement park.

This overlooked street light once served as a KGB dead letter box.

Originally built as a promotional giveaway, this suburban house was designed to be an IRL version of the Simpson home.

One of the earliest large-scale "hyper" roofs in the U.K. is now a derelict roadside attraction.

This mysterious, medieval cathedral remains unbuilt but fiercely protected.

One of the largest wooden constructions in Europe was meant to be a casino, but soon became an orphanage.

One lonely, modern pyramid has gone from corporate think tank to deserted boondoggle.

A former reservoir that was only recently discovered after more than 60 years of disuse.

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.

The Arctic Archipelago is home to world's largest third order island: an island in a lake on an island in a lake on an island.

The only parking meter in the entire town, it is surrounded by 100 free spaces.

This magnificent Japanese garden provides a moment of Zen in rural Vermont.

Georges Seurat’s pointillist masterpiece has been recreated in Ohio in topiary form.

This elegant neoclassical garden is a peaceful oasis in the middle of the Nepalese capital.

A little slice of Japan and its aesthetics in London's Holland Park.

A memorial to the first person killed by a motor vehicle in the Western Hemisphere.

The mysterious image is believed to show Edward Hyde, 3rd Earl of Clarendon, in a beautiful blue dress.

Curious crustaceans support an obelisk from ancient Egypt that now stands in modern-day Central Park.

This whimsical group of statues is a favorite of children who love to climb all over Lewis Carroll's beloved characters.

Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

This centuries-old mine remained hidden beneath a hotel bar until 2013.

Hidden in an ordinary Midtown building is a one-room museum dedicated to the greatest escape artist.