Colonial architecture meets urban art in this sprawling open-air gallery.

The small cave that housed Tennessee's "first citizen."

This award-winning men's bathroom was just too beautiful to not allow women to see.

Known as the "Cross At The Crossroads," this massive metal cross is just short enough to avoid the FAA.

The colorful stairs are made with marble from the world's major quarries.

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

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

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

Yo, Adrian!

A tour de force of a fountain, memorializing a man who loved fountains more than anything else.

A daily replay of the experiment that proved the rotation of the Earth.

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

The sounds of the world's largest fully functioning pipe organ dazzle shoppers at a Philadelphia Macy's.

The first American department store, and home to the largest operating musical instrument in the world.

Current docking place of the SS United States, the fastest transatlantic ocean liner.

This little-known Revolutionary War fort is supposedly haunted by the ghosts of its past.

These lush botanical gardens employ the most purrfect pest control force.

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.

The longest covered bridge in Delaware.

A blend of art, antiquities, and Americana fill this museum, surrounded by whimsical, enchanting gardens.

This splendid Versailles-inspired mansion has the largest French-style formal gardens in North America.

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

This weeping, 10-foot-tall sculpture was a maquette for a 9/11 memorial.

Although built to generate electricity for Marylanders, this dam has become an all-you-can-eat buffet for American bald eagles.