Resonating tubes make music from highway overpass.

Here, visitors can swing with the waves of the Pacific Ocean.

The most confusing clock in New York.

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

A hands-on traveling collection of the innovative devices of yesteryear.

An unassuming secret door once led to a legendary watering hole.

The original toys that inspired the beloved children's stories are on display at the New York Public Library.

The fanciest public restroom in New York City boasts fresh flowers, art, and a classical music soundtrack.

Commemorating the spot where the famous scientist fed his pigeons.

Hidden in plain sight on a pair of Manhattan subway tunnels are a pair of public instruments that sing to each other.

There are owls with glowing eyes in Herald Square.

There must be a pun in this haystack somewhere...

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

Just a man taking his prehistoric pet for a stroll.

The site of the first "historically true" UFO encounter in the U.S.

Collapsing castle on the Hudson river was once the storage site of military surplus business.

A hidden network of subterranean passageways lies tangled beneath Indianapolis' bustling City Market.

The bespectacled, cocktail-sipping pachyderm is a strange but fitting liquor store mascot.

Over 100 concrete munitions bunkers are all that remain of a Pennsylvanian village seized by the US government.

This 19th century granite fortification is one of the most well preserved forts in New England.

This massive solar system model is sprawled out across Maine's suburban wilderness.

Once adorning a New York skyscraper, these reclaimed ruins now haunt an Indiana park.

The often-overlooked ruins of one of the first buildings designed by famous landscape architect Frederick Olmsted.

An enormous, inside-out glass globe built in 1935.