This scenic Maryland park was the site of one of the worst prison camps of the Civil War.

This simple stone memorial remembers a secret, Geneva Convention-defying interrogation base from WWII.

A double agent hid information for the Soviet Union beneath this bridge for more than 20 years.

America's first federal monument.

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

The site of the climactic scene from the classic horror film is now a historic landmark.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

Home to items never before seen by the public.

Vacant Beaux-Arts buildings that serve as reminders of a beach town’s glory days.

Touching mementoes from those who didn't make it back from World War I still hang in one of New York's oldest bars.

Naturally formed white marble arch housed in an abandoned marble quarry from the 1800s.

Over fifty whirling pools left by the glacial age.

An old trolley bridge was converted into a breathtaking garden bursting with colorful flowers.

A grand Gothic Revival basilica with stained glass depictions of Montreal's religious history has only one soul resting in its crypt.

This 1967 experiment in modular architecture was designed to be a new model for urban living.

Designed by Buckminster Fuller, this relic of the 67 Expo survived fire and ice.

Futuristic apartment blocks are the backdrop for Montreal surfers hangin' ten on the Habitat '67 standing wave.

A wall of chewing gum moonlights as collective art.

A walk through the historic city center, under the streets of Seattle.

This long, dark tunnel is open to hikers, but those without lights are known to get confused even on the straight path.

One small town in the Pacific Northwest transformed itself into a Bavarian-themed tourist destination.

The second-largest gold nugget in existence, displayed in a Las Vegas casino conveniently named the Golden Nugget.

Oddly shaped rock formation, misassociated with a nearby utopian community.