All that remains of the Whittall mansion are the ruins of the formal garden and its pergola, dedicated to the late Matthew J. Whittall by his widow.

A once extravagant mansion, now reduced to ruin.

A 10-foot-tall concrete Alley Oop statue left over from World War II now stands on the side of the road.

A forsaken wonder in the middle of the East Side neighborhood.

A Neolithic burial site built 1,000 years before Stonehenge.

This abandoned gun tower was built to defend the River Thames from a French naval attack.

The Neolithic megalith was one of the first archaeological ruins protected by the British government.

A beautiful, creepy 19th-century castle stands incongruous in rural Vermont.

Possibly the smallest church in the world floats in the middle of a pond.

Eighteen miniature death-scene dioramas.

This collection of ferns from across the globe is the largest assortment in the United States.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

A perfect replica of the beloved show's first set.

The great American road trip, but smaller.

An unexpected canine grave atop a mountain.

All that remains of the once-booming chain is a single orange-roofed restaurant.

A mysterious echo seems to defy the laws of acoustics.

The gilded vestiges of a sterling department store can still be found in a Brooklyn shopping center.

Dodge prohibitionists and slide through the telephone booth in Crif Dogs.

This little museum is built on a theater that was once a wildly elaborate speakeasy.

Visible below the waves are memorials to the city's Gold Rush dead.

There is no trying to fall in love with this Star Wars fountain, you just do or do not.

It's clear this abandoned Art Deco gem was no ordinary cleaners.

Made of giant chains and hung with shackles, this iron cross honors those unknowns who perished under American slavery.