Extreme Homes

Dwellings include a glass box in Switzerland, an outlaw cave in the Arkansas wild and a pyramid in rural Ohio.

This amazing assortment of homes from all over the world includes a house hidden behind a wooden grille in Italy, a wave-form residence in California and an Austrian residence that's rusting beautifully. Lithuania has a round house built from sticks while there's an all-American house in Japan, a topsy-turvy home in Brazil has everything upside down and there's one in Australia that looks like a fence. Spain goes for the spaceship style, a house in Arkansas towers above the forest while one in San Francisco defies gravity and in Argentina a home takes the molecular approach and is light, incredibly strong and surprisingly portable.

This amazing assortment of homes from all over the world includes a French bubble palace, a house in Virginia where the building materials dictated the style, a Dutch rhomboid-shaped residence and one made from soda bottles in Argentina. Two become one in Hong Kong, while a house in Portugal combines excitement with economy, a home in Wisconsin spirals out from solid stone and an Italian residence is a tiny cube. Australia has a live-in library, a home in Montana combines silver stainless with raw rusty steel and a Japanese house mirrors the world.

This amazing assortment of homes from all over the world includes an Australian house based on the shape of the letter K, one like a giant Monopoly piece in Portugal, a Californian home inspired by a lotus flower and a Japanese residence that looks like a subway station. A French home looks like an eye gazing over the Mediterranean, Austria has a futuristic portable pod inspired by nomads, there's a house shaped like a hammock in Paraguay and South Africa has a high-tech mountain house. A closet project turned into a whole house in California, a fairy tale inspired a snake-like home in Lithuania and a car elevator leads to a cliff-face residence in Laguna Beach.

Featured: an English home built beneath a wildflower meadow; an Australian abode perched atop a 1000-foot cliff; and a home constructed out of old shipping containers in Chile. Also: ruins in Portugal; a PVC bubble in France; a California residence perfect for performing arts; an ode to black and white in Hollywood; a Brazilian fig-tree house; and a glass farmhouse in Oregon.

The word extreme means different things to different people, and to these homeowners it means pushing the envelope as far as possible. From construction to completion, take an up-close look at some of the world's most spectacular houses ever built, from a castle made entirely of mud to a home shaped like a sphere, from one built deep in a cave to a home that looks like a snake, and find out what makes them all so unique.

Featured: a guarded mansion in South Africa; a home that resembles a flashlight in Portugal; a Dutch abode made out of glass triangles; a London apartment with a hole cut in the center of it; and a Japanese residence made partly from tires.

This amazing assortment of homes from all over the world includes a South African residence complete with two human-size nests, a Californian home that blends into the landscape and a Japanese home that is left open to the street because it has no doors. There's a dwelling no bigger than a shed in Oregon, a Brazilian residence that also houses thousands of books, a tree house made from recycled materials in Texas and an Australian home inspired by a mythical creature called a gryphon. Country living and cutting edge design collide in France and a Mexican house zigzags down a hillside while a once-ruined English hunting lodge is perfect for parties and a residence in California features a human aquarium.

Castle, Factory, Cliffside

This amazing assortment of homes from all over the world includes an American home which is like discovering a lost civilization, a house in Japan shaped like a staircase, one in South Africa which is so well-camouflaged that it almost vanishes into the wilderness and an Australian residence whose owners think they're living on Cloud Nine. Germany has a six-story wedge, Mexico has a seaside home made out of a bridge, every exterior wall possible has been made out of glass in Oakland and there's a self-styled temple to the gods in France. A Norwegian house nestles in a tree, a Portuguese one honors a whole forest and there's a pyramid home in Seattle perched on top of a skyscraper.

Greenhouse, Nest, Secret Agent