A park where you can watch the highway zoom past.

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

A 30-year-old Sycamore tree grown from a seed taken to the moon and back.

This piece of peacetime naval wreckage memorializes the tragic sinking of the USS Maine--an event which sparked the Spanish-American war.

See four top-secret US spy aircraft of the Cold War era, including the legendary SR-71 Blackbird and the A-12 Oxcart.

A real-life hidden Easter Egg in New Hampshire's capital city

The "World's Largest Underground Business Complex," a 55,000,000-square-foot city underneath Missouri.

The official atomic museum of the United States explores the explosive and productive history of a much maligned energy source.

Lost subway station nestled beneath Toronto's busy commuter line.

This plaque is dedicated to one-half of the Magliozzi brothers and their hit radio show, 'Car Talk.'

The hidden jewel of Disneyland: a members only playground for the Disney elite.

The "3rd largest" city in California is an empty mirage of suburbia in the middle of nowhere.

The Mysterious Witch Bonney, a haunted statue in an old industrial city.

This tiny, painted door at the base of a tree stump has been a fixture of the Harvard University campus for decades.

This location of a Mexican chain restaurant has a unique location: an old jail.

The classic Christmas carol was written at this Massachusetts tavern in 1850.

This rare, carefully curated collection showcases the history of neon inside a grandiose Elks lodge.

This museum is dedicated to the first coast-to-coast highway.

A decomissioned facility where the German "Transrapid" maglev trains were once tested.

This historical air terminal in Houston is slowly becoming an aviation museum dedicated to the city's aeronautical history.

This museum showcases the history and contributions of the U.S. Army to the medical industry, both on the battlefield and off.

Decaying military base deactivated in the 70s is now visited by urban explorers and military enthusiasts.

Turning night into day in Victorian-era Austin to thwart a serial killer.

A huge musical sculpture and other art installations on the National Oceanic and Atmospheric Administration grounds.