This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

One of Canada's most incredible rare book collections holds hundreds of thousands of gorgeous tomes that the general public can touch.

A saloon and inn that served the Wild West's most iconic figures—and is still haunted by some of them today.

This store also houses a museum dedicated to the history of these small, historic community shops.

This subterranean oyster house has been the pearl of Grand Central Station since 1913.

The United States's largest hand-dug well is topped with a state-of-the-art museum.

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

There was a top secret plan during World War II to seal a group of soldiers inside the rock.

The only structure left with direct ties to the Salem witchcraft trials of 1692.

Classic game cookery takes center stage at what's widely considered London's oldest restaurant.

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

This sinkhole was created by a tragic industrial accident and continues to ravage the surrounding landscape.

Installed as a beacon of hope for a hurricane-racked island, the statue had to be moved multiple times due to the eroding coast.

This abandoned Civil War fortress is slowly being swallowed by the waters of Lake Borgne.

A miscalculation turns a very shallow freshwater lake into a very deep saltwater lake.

This Art Deco airport was once deemed “the air hub of the Americas.”

The first American home of the isolated, egalitarian religion has a trove of Shaker architecture and artifacts.

America's oldest Eastern European synagogue provided the immigrants of crowded Lower East Side tenements a space of sanctuary.

The home of 1.5 million wood letters for printing is still a functioning workshop.

Literally a million fascinating cartographic artifacts are held in this sprawling university collection.

A bypass decorated with large wooden troll carvings.

"World's largest scrap metal sculpture" stands in an outdoor sculpture garden in the middle of Wisconsin.

The New England cabin where an infamous British occultist conducted experiments in "magick".

Birthplace of America's first documented serial killer.