Inside houses a vast collection of military aircraft and missiles spanning the ages.

This bridge uses an inverted bowstring truss and is believed to be the only of its kind in the United States.

The largest ancient burial mound in Ohio.

Mussolini gave Cincinnati a bronze statue of Romulus and Remus suckling at a wolf's teats.

The remnants of two World's Fairs are here, complete with a 12-story globe, a mini-Manhattan, and a UFO-shaped pavilion.

100 massive sculptures in the Hudson River Valley.

Reclaimed by nature, the ruins of Doodletown, New York are remnants of a town consumed by a state park.

Decades after testing the polio vaccine on unwitting patients, this historic mental hospital sits in ruin.

The house that birthed The Old Man and The Sea is now a museum devoted to the old man who wrote it.

A focal point of the Cuban government, this city square features one of the most iconic images in the country.

His music once banned in Communist Cuba, John Lennon is now immortalized in bronze by Castro, who considers Lennon a "fellow dreamer."

Millions of years of oxidation make a drive down this winding Death Valley road surprisingly colorful.

The lowest point in North America is home to an undrinkable pool surrounded by fields of geometric salt flats.

The scars of World War II are preserved on its walls.

The granddaddy of all tourist traps, built on ice water, jackalopes, and a giant dinosaur.

A fitting attraction for the corn capital of the world.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

An unusual, super-sized grocery adventure awaits in an Ohio suburb.

This innocent-looking townhome is actually a subway exit.

The feral felines of Roosevelt Island have a small army of allies and an abandoned hospital all to themselves.

A time capsule of Floridian history fights to survive on the banks of Chokoloskee Bay.

One-time winter retreats of prolific inventor Thomas Edison and his friend Henry Ford.

Former utopian colony based on the belief that the universe exists in a hollow sphere.