The lush coastal city of Astoria is riddled with forgotten secret sidewalks.

An eccentric inventor's castle home with its own indoor weather system.

The intriguing personal collection of a professional demon-chaser.

The attic and basement house two museums stuffed with oddities like swallowed spoon handles and a shrunken head.

The remnants of a 19th-century ironmaking complex hidden in the woods of Connecticut.

This dam in the woods, built by Henry Ford with only manpower and oxen, holds no water and serves no purpose.

This tower pays homage to a legendary Viking fort established in Massachusetts that never really existed.

This castle constructed in 1928 was crafted from drawings of Lismore Castle in Ireland.

Located in a beautifully restored ice house, this museum is the result of decades of hard work and devotion to the craft of plumbing.

Order “Proletariat’s Cutlet” at this communist-themed restaurant allegedly once visited by Lenin.

The world’s narrowest house makes for an awkward, four-foot-wide living space.

A 20th-century picture show in 3-D.

This hidden collection of everyday objects illustrates life within communist Poland.

Beneath Kraków Old Town's main square lies a hologram-filled medieval market vampire graveyard wonderland.

Iceland's only steampunk shop imagines a retro-futuristic world that never was.

A reliquary of pop culture marvels, including the world's largest (and most terrifying) Jack-in-the-Box.

This petite park lets visitors see and touch examples of fossilized dinosaur tracks.

The sunken structure looks like the victim of a catastrophic flood.

Taking the 3D art experience far beyond blue and red glasses.

This Oregon farm is dedicated to teaching people the professional art of tree climbing.

This unassuming cheese empire in rural Oregon churns out more than 150,000 pounds of cheese each day.

The largest wooden building in the world now houses a fascinating collection of aircraft.

This rare, carefully curated collection showcases the history of neon inside a grandiose Elks lodge.

Nestled between a college and a golf course, the garden is home to more than 2,500 rhododendrons.