A giant Troll lurks under one of Seattle's oldest bridges.

A remote horde of architectural treasures fit for Indiana Jones.

This abandoned asylum was once a state of the art facility before devolving into one of the most deadly mental institutions in American history.

This dig site outside D.C. is known for its exceptionally high density of baby dinosaur fossils and dinosaur eggs.

A lawn full of retired spacecraft on display at one of NASA's first research labs.

The Forest Service's surprisingly sophisticated collection of wildfire prevention art features America's most beloved bear.

Two dozen pinball games hidden away inside a most unlikely location.

The haunting "Hell House Altar" is one of the few remnants of an abandoned college that has been a magnet for local legends.

A local farm's collection of unusual structures from a now defunct storybook amusement park.

The 320-year-old tree that greeted General Lafayette and rerouted an interstate highway.

A lovely aquatic park built by a one-armed Civil War veteran who made a fortune from lotuses.

What remains of the summer palace of King Kamehameha III.

Politicians, bureaucrats, and military officers gathered in this field near the Capitol to settle their disputes with blood.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

Island where motor vehicles are banned -- home to the only carless highway in the United States.

The remains of a failed attempt at medieval nerdery are hidden deep in the woods of Virginia.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

This colonial tavern played host to George Washington, Thomas Jefferson, and other famous early Americans.