A concrete mushroom that divided Stockholm residents for nearly a century.

A condensed piece of China floating in a Dutch harbor.

An unsettling sculpture of a boy hanging out in a street in Ghent has been baffling visitors for years.

This quarter-mile tunnel under the Bluff in Pittsburgh bends at a 45-degree angle.

Formerly the world's largest, this Willy Wonka-esque contraption runs 24/7.

The tallest church in Mechelen might have been the tallest in the world if not for a lack of funds.

This cathedral dedicated to Louis IX, sainted King of France, holds many secrets.

A stunning, two-tiered waterfall made famous by poets, artists and the legend of a ghost dog.

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

Everyone from Mark Twain to Teddy Roosevelt has a pipe hanging from the walls of this historic chophouse.

Finally, you don't have to be a pious Swedish seaman to relax like one.

The most confusing clock in New York.

This simple Manhattan salt house is artfully shaped... well, like a giant granule of salt.

Rummage through this sunken ship, but leave your scuba gear at home.

This was one of the first (and last) university-built and operated nuclear reactors.

This unmarked and unloved Manhattan subway grate created one of the most iconic images in American cinema.

The oldest Methodist church in the United States has been spreading the good news for over two centuries.

One of only two commuter aerial tramways in the United States.

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

Under a glass sidewalk lie the remains of some of Manhattan's oldest buildings.

This beautiful building in the heart of Manhattan's Financial District was empty for decades.

One of many reminders of Tesla's scientific contributions overlooks the falls which inspired him.

The highest point in the state of New Hampshire, and while unlikely "the worst weather in the world," it sure seems that way to hikers.

The sweetest graveyard in the world is filled with headstones for dearly de-pinted ice cream flavors.