The headquarters of the Audubon Naturalist Society is a small slice of heaven for nature lovers.

Three abandoned missile silos are hiding in plain sight behind a suburban development in Maryland.

Electronic inventions that resulted in products and systems we use every day are on display in this labor-of-love museum.

A Civil War Museum with some notable medical antiques.

A remarkable time capsule of American manufacturing deep in Maryland coal country.

This abandoned sea fort has become an accidental bird sanctuary.

The remnants of a wooden-hulled fleet built and abandoned in WWI, now home to a thriving ecosystem.

A priceless collection of the Nation's cryptologic history.

The land is home to swimming ponies and a legendary 18th-century treasure.

Bizarre Cavern.

This local gem houses the largest collection of pre-Raphaelite paintings outside of the U.K.

A grotesque Fiji merman dwells within this traditional Dutch-style building.

A scenic fort on the harbor protected Philadelphia from an attack that never came.

A monument to the sheer amount of oddities one can collect over a lifetime.

This labyrinth was designed to help visitors focus and meditate.

Rising out of a clearing in New Jersey's Pine Barrens is an Aztec-inspired monument to the "Lindbergh of Mexico."

In the heart of the Pine Barrens, entire forests of pitch pines that usually grow 20–90 feet tall only reach six feet in height.

World War II bunker still standing on the New Jersey beach.

This historic iron-working village is now a ghost town so immaculate that it looks as though it was recently built.

In the woods of New Jersey lie the ruins of a munitions village abandoned after World War I and the remnants of a 1920s wooden racetrack.

Used as a military post in three different engagements, this fort has remained incomplete and unfired upon for nearly 200 years.

The mounds on this coastal archaeological site reveal the history of the land’s first inhabitants.

This natural spring is the winter home to the largest gathering of manatees in the world.

Ruins of an old sugar mill sitting quietly next to a park in rural Florida.