A series of modernist treehouse hotel rooms grace the outskirts of an Arctic forest.

An Amazonian hotel is the ultimate treehouse and provides stilt based accommodation.

Part modern art project, part traditional chapel, this see-through church is only substantial from the right angle.

This Greek temple, open only an hour a day, was the site of a war of tastes between an architect and an artist.

A Buddhist theme park brings you a Buddhist version of Hell.

The largest stone moai on Rapa Nui.

The self-mummified monks of Japan.

On Japan's Tashirojima Island, cats are king.

This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

A hand-built folk art installation covered with messages of God's love.

An Aztec snake god has taken the material form of an apartment complex.

This "social palace" housing complex created a relatively stable and self-contained worker's society... for a time.

Try not to get lost in this picturesque Brazilian labyrinth of the dead.

This chilly Canadian hotel has a four-month lifespan due to the unusual material it's made of.

One Italian taxi driver covered his entire house in small seashells creating a weird bit of architecture that is preserved to this day.

Giant eggs, walls of bread, and nightmare surreality mark the largest collection of works by Salvador Dalí.

World's largest porcine hairball sits in a collection maintained by Benedictine monks.

The once forbidden "secret cabinet" of erotic art from excavations of Pompeii and Herculaneum.

Rebuilt remains of a temple to Roman god Mithras.

A deadly ancient portal to the underworld.

Highly unusual subterranean stupa and adjacent cave monastery.

Ancient rock-hewn town that witnessed key events of Georgian history.

The old Niles Canyon Aqueduct in the San Francisco Bay Area is a bemusing and secret trail through nature for wayward travelers.

Costumed elves and mountain bikers co-exist peacefully at this abandoned Christmas-themed adventure park.