A cannon designed to fire an atomic warhead.

A fitting attraction for the corn capital of the world.

Self-built house and sculpture park where the creator can still be seen in a glass coffin.

This Italianate Villa-style castle is pretty to look at, just keep off the private property.

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

The Bucyrus-Erie model 1850B electric shovel, or "Big Brutus," the largest existing electric shovel in the world.

The curios of pharmacist and collector Henry Wellcome.

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

Antarctica's bustling metropolis, originally established by Richard E. Byrd.

The highway's southernmost spot is a beloved local attraction.

The world’s largest combined collection of U.S. and Russian aircraft got its start in a poultry building.

The US Navy's only submarine museum is also home to the world's first nuclear submarine.

Man-made geyser that rises to the exact height of the Gateway Arch.

A historic presidential getaway on the continental United States' southernmost island.

This enormous World War II relic is one of the largest wooden structures in the world.

This now-deactivated naval base defended the Florida coast for centuries.

This monumental Jesus is often referred to as "Our Milk Carton With Arms."

This small-town pizzeria won the Hollywood lottery.

Once America’s most beautiful army base, this abandoned military fort on the coast of Monterey Bay has been left to the elements.

Air Force Academy Chapel made of 100 identical tetrahedrons works to inspire those of all religions.

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

You have to love a museum with a truly dedicated focus. A focus on Superman, for example.

This erect, phallic geological spire wasn't always named so domestically.

One of the only Florida forts to remain in the hands of the Union all through the Civil War still stands as a historic stronghold.