A striking 12th-century-style castle built on the edge of a cliff.

A German town is growing a building out of trees.

Built to test magnetically levitated elevators, the tower also boasts Germany's highest visitor platform.

This road in the Great Smoky Mountains was supposed to assuage a displaced community, but ended up a $52 million dead end.

This serene bamboo walkway allows Buddhist monks from remote temples access to the nearby village.

Colorful clay cliffs tower over an unofficial nudist beach on Martha's Vineyard.

The watery grave of Captain Bligh's famous ship.

The cafe that acts as the social hub for the small volcanic island of HMS Bounty fame.

Remote, volcanic island that Darwin, Hooker, and the Royal Navy shaped into a thriving, artificial ecosystem.

This Nigerian nature reserve is home to the longest canopy walkway in Africa.

An abandoned, desolate train tunnel that was used during World War II.

The world’s highest ski resort was deserted after an 18,000-year-old glacier melted away.

This quaint funicular has been ferrying people up and down an English valley since the Victorian era.

Abandoned for 60 years, this submerged bridge was completely forgotten until the lake was drained.

The longest navigable underground river in the United States is home to countless blind and albino animals.

An eccentric company offers eccentric millionaires the opportunity to have spaceflight-related experiences.

A bunker "with enough U.S. currency to replenish the cash supply east of the Mississippi" in the event of nuclear war now protects nitrate film.

This historic mansion was built as a symbol of love between a husband and wife.

A former mental hospital founded in the 1930s by a eugenicist who advocated for the forced sterilization of patients.

The skeletal white beams stand as a monument to religious dissent.

An alternate history park where the Union Army loses the war... to dinosaurs.

Nine of the very few concrete ships ever made in the U.S. are beautifully decaying off a Virginia pier.

The ruins of this Thomas-Jefferson-designed mansion have been left to crumble since the Christmas Day they burnt down.

The flower-shaped temple in Virginia aims to transcend the boundaries of the world’s religions.