The longest continuous lava tube in Oregon.

Massive crater in central Oregon.

Home inspired by the crystal rock formation of the Emerald Estates.

A 30-acre garden inspired by the principles of modern physics.

An intricate and amazing house built by architect Karl Junker.

One of the deepest indoor swimming pools in the world.

Ancient man-made caves underneath small town Belgium.

A varied collection of brains in alcohol.

A former plague hospital turned medical museum.

An underground mansion with fruit-bearing trees and grapes growing beneath the surface of central California.

Collective dedicated to restoring steam engines.

Once thought to be the oldest living tree in the world, Methuselah was germinated before the Egyptian pyramids were built.

A storybook European village in Berkeley.

This Elizabethan hedge maze is one of only six in North America.

Surprisingly Delicious Asian-Style Hot Dogs.

A gargantuan crystal kingdom.

Stalactites and stalagmites in a beautifully lit cave.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

The fairy tale castle of the "fairy-tale king."

A peculiar mansion built by the troubled heir to the Winchester Rifle Company fortune.

The fossilized remains of ancient California redwoods.

A Boeing mechanic and his wife leave a whimsical, stone sculptured garden as their legacy.

Marvel of green building techniques that sings with the wind.

Treehouse motel and treehouse-building school.