Berkeley Hot Springs presents to you "the only outdoor monument to presidential bathing."

A star fort along the C&O Canal in western Maryland that protected America in three wars.

Easter in Westminster may be the only time and place to behold Edgar Allen Poe made entirely of Marshmallow Peeps.

Home of the only civilian casualty at the Battle of Gettysburg.

A girls' boarding school inspired by the Chicago World's Fair, once abandoned, now restored to strange and scenic glory.

An eerie, decaying ghost town destined to fade into the forest.

A cave on the Maryland border where civilians took refuge during the bloodiest battle of the Civil War.

One of the only memorials dedicated to journalists who died in combat.

Built by the patriotic residents of Boonsboro in a single day.

FDR's Art Deco hospital tower was hopelessly inefficient.

Rediscovered after a century, the father of the American Navy was reinterred in something dredged up from Davy Jones' Locker.

A Civil War Museum with some notable medical antiques.

A museum dedicated to exhibiting remarkable outsider art.

This elaborate towering structure was once famed for its revolutionary height.

This palatial botanical garden is home to one of the largest pipe organs ever installed in a private residence, and a piece of Wood's cycad.

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.

World's first "penitentiary," meant to be humane, drove men insane.

Clap your hands at the base of the pyramid, and the song of a sacred Mayan bird will echo through the air.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

Every equinox this Maya pyramid puts on a spooky ancient light show.

After Christopher Columbus died, his son built a fancy house to rule from.

Built in 1512, the oldest cathedral in the Americas.

The final resting place of Christopher Columbus - or possibly someone else.

Famously misunderstood wonder of the ancient world