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

This massive steel pyramid can be entered by a set of jagged steps that let visitors stand in its heart.

This monolithic slab of art metal crowns a German slag heap.

Tucked away in a small German apartment is an eclectic museum devoted to West African vodun culture.

The monumental home of Prussia’s eccentric "Cannon King."

The Bauhaus-style former industrial complex is considered the world's most beautiful coal mine.