Commonly acknowledged as the only public monument to the Devil himself.

A lush indoor jungle fills this bustling Madrid transportation hub.

An ancient Egyptian temple in the middle of Madrid, Spain.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

France's most famous cemetery, with some of its most curious tombs.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

A six-story, asymmetrical tower filled to the brim with scientific experiments.

The architect of this fanciful complex called it an "oasis for humanity and nature in a sea of rational houses."

This 17th-century "unicorn" was cobbled together from the skull of a rhinoceros, the legs of a mammoth, and the horn of a narwhal.