Dutch woodpile home in the forest.

Between Neo-Pagans and Neo-Nazis, these strange rock formations have a curious cult following and a very strange history.

An intricate and amazing house built by architect Karl Junker.

Stay in a room with a view... of the bottom of the ocean.

Former villa and estate of James Deering developed to preserve native tropical forests.

A community of collapsing homes more than a mile out from the Florida coast.

A mysterious castle built as a monument to lost love.

The largest self-built castle in the U.S., six decades in the making.

A small Portuguese cottage formed between boulders in the countryside.

Houses are tucked between, on, and underneath giant boulders.

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

Stalactites and stalagmites in a beautifully lit cave.

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

The "World's Largest Underground Business Complex," a 55,000,000-square-foot city underneath Missouri.

Town of spiritualists and mediums in Florida.

Possibly the most beautiful carillon in the world, set atop Iron Mountain in Florida.

Florida castle built with aluminum printing plates.

Former utopian colony based on the belief that the universe exists in a hollow sphere.