A haunting collection of the vanished and disappearing natural world.

A hospital where antique dolls are given new life.

Hidden beneath a restaurant, underground tunnels tell the story of Malta’s tragic role in World War II.

A giant interactive periodic table with real samples of the elements.

Countless grotesque faces stare out from this eerie Prague art wall.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

The single richest source of elemental discoveries in the world.

No one knows who's responsible for decorating this tunnel with stuffed animals, but the people love it enough to protest their removal.

Street artists transformed this abandoned industrial neighborhood into one of Europe's largest graffiti exhibitions.

A man has revenged his true love's betrayal through tears and stone genitalia.

A hidden bathhouse in one of Stockholm's oldest and busiest neighborhoods is open to anyone who can find it.

An enigmatic modern marker left next to a historic Roman site.

St. Francesca Romana, patron saint of drivers, resides in the church she founded.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

The Pope’s secret escape route.

Rome's semi-secret peephole vista is also a former Crusader stronghold.