This old ruin once served as a post office, a train station, a restaurant, and a bridge to the Atomic Age.

Once a dining hall for boarding school students, this lodge was a popular haunt for nuclear physicists working on the Manhattan Project.

Thousands of pieces of art have been carved into the rock at the site of an ancient volcanic eruption.

This museum started as a collection of Manhattan Projects and continues to add exhibits as they are declassified.

A small metropolis of Pueblo cave dwellings have been carved right into the hillside of this national monument.

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

It's easy to see why this eclectic architectural wonder has been dubbed the "Spaceship House."

A museum devoted entirely to the rattlesnakes and snake-related art.

Sections of the iconic limestone columns have been left uncleaned as a reminder of the city's polluted past.

A model of a dinosaur that was named for Andrew Carnegie stands outside the museum that also bears his name.

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

The actor best known for slapstick comedy is memorialized in his home town.

A restored Pittsburgh house of God has been converted to a marvelous house of suds.

A collection of colorful dinosaurs hidden in an actual rainforest.

Two mammoth statues inspired by equally tall tales lure tourists to this roadside attraction.

A tourist attraction founded around a slumping cabin.

This natural marble cave is one of only five national monuments in Oregon.

Treehouse motel and treehouse-building school.

Apartment building was once posh playground to the Hollywood elite.

The Master of Magnetism dominates the walls of a scrap metal yard to keep graffiti artists at bay.

The first home of the doomed aviatrix Amelia Earhart.

The history of the treatment of mental illness, illustrated in all its gory detail, and housed in an asylum.

A beautiful footbridge with over 2,000 glass sculptures along the walls and ceiling.

A Roman-style column in Oregon hides a spiral staircase inside.