An ornate private entrance to the Vienna subway built specifically for the emperor.

A rooftop restaurant hides in plain sight atop Vienna's Palace of Justice.

A memorial in the Tiergarten is a reminder of the suffering inflicted on homosexuals by the Nazi regime.

A unique Holocaust memorial tells the personal stories of the Jewish residents exiled from greater Berlin.

Lava stone structures possibly dating back to the 19th century may have been a stopping point for voyagers between ancient Egypt and the Mayan Civilization.

Hundreds of caves once used to store grains and animal feed.

Men in rubber-soled boots serve as your "brakes" on this toboggan ride Hemingway described as "exhilarating."

The corpse bride of Portugal.

Picturesque intersection of witchcraft and ancient Christianity.