This hidden park hosts a rogue’s gallery of eccentric architectural obelisks.

The debris forms a solemn memorial to those who died in a 1963 accident.

A six-story treehouse offers spectacular views of New York's Finger Lakes region.

A nature and cultural preserve named for its multitude of petroglyphs carved by the Northern Sinagua people.

A collection of intricate sculptures so small they have to be seen through a microscope.

All aboard the world's longest miniature railway.

A careful eye can find hundreds of dinosaur tracks running along the Connecticut River.

A small museum along the Susquehanna River is home to a rich collection of Native American artifacts.

A mysterious inscription may hold a clue about the "Lost Colony" of Roanoke.

A half-mile long and three stories high, this bridge over the Des Moines River Valley mimics a descent into a mine shaft.

The site of the little-known Pennsylvania battle that sparked the Seven Years' War.

Maryland's first (and last standing) toll house on America's first federal road established the state as the "Gateway to the West."

The antique hotel still has a jail in the basement, though the cockfighting ring is long gone.

This secluded walking trail is a hidden gem of a Pittsburgh park.

A unique botanical garden housed in three giant geodesic domes.

The Virginia home of one of the signers of the Declaration of Independence is being preserved with a unique glass facade.

Solving a 60-year mystery finally gave a name to the young woman known only by the color of her clothes.

A plaque commemorates the spot in the Oregon woods where the first-ever Geocache was hidden.

The only natural lake in the world that drains into both the Atlantic and Pacific Oceans.

The enormous 250-room Vanderbilt mansion conceals hidden doors and secret passageways.

This spectacular bridge supported by two gigantic hands looks like something out of a fantasy universe.

A tiny, remote island packed with wonders both natural and geeky.

A hidden beach at the end of a tunnel of mangrove trees.

These eerie outliers of the lightning bug family glow a mysterious blue color.