This giant wooden treehouse within a sprawling garden has its own eatery.

The only structure left with direct ties to the Salem witchcraft trials of 1692.

America's smallest national park site is the former residence of exiled Polish national hero Thaddeus Kosciuszko.

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

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

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

Frank Lloyd Wright's most iconic home dangles over a Pennsylvania waterfall.

Mysterious rocks that ring musically when struck.

An ancient Scottish rock formation said to be the gravesite of a giant remains ensconced in legend and intrigue.

The unusual patterns in this rock formation result from two distinct modes of weathering.

The land is full of geologic eye candy, such as otherworldly spires, mushroom-shaped hoodoos, and prehistoric fossils.

A long, winding trek rewards you with a gorge so captivating it inspired a painting in the Tate.

The oldest surviving presidential residence in the United States.

More than 21,000 images fill this overlooked gem of a prehistoric site.

In a largely deserted ghost town, a little brick building recalls its history as a gold rush hub and haven for outlaws.

An abandoned castle owned and ignored by Masons carries a cursed history.

Hundreds of glow-in-the-dark objects light up a museum in a historic zinc mine.

Where the famed frontiersman was born, raised, and survived Quaker intrigue

The mysterious, fantastical woodland inspiration for "The Lord of the Rings."

One of the oldest train stations still standing in Virginia played a vital role during the Civil War.

A "house to which to flee" for settlers in colonial Pennsylvania.

This historic train station has been converted to a locomotive themed hotel.

This "Plant Farm Museum" is home to the divinely inspired and visionary outsider artwork of Reverend Howard Finster.

Giant origami sculptures tucked into desert scenery beckon passers-by to explore further.