No need to strap in for a "ride" on this walkable roller coaster.

This medieval castle overlooking the Elzbach river looks just like it did hundreds of years ago.

This "floating railway" is one of the world's oldest monorail systems.

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

Art from the latest counter-culture; kids who dye their hair blue and believe the future will be a post-apocalyptic water world.

The graffiti-covered remnants of a former triangulation station are balanced precariously on this California peak.

The neon signs from Las Vegas' past find their final resting place at this unusual graveyard.

This ruined folly was originally built to honor a failed American state that would have become "Westsylvania."

One of the largest mechanical models of the solar system in the world.

The tower was originally used as a chimney for the waste incinerator of St. John's Precinct and Market.

A hundred copies of Antony Gormley's naked body stare out across the water.

The second-longest pier in the U.K. stretches a whole kilometer into the Irish Sea.

Giant statue of a disembodied head.