A centuries-old forgotten underworld lies beneath Malta.

Two geological phenomena in one precarious locale: a towering stone window, and a deep blue void.

The world's most active stratovolcano is almost always erupting.

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

This historic island prison holds one of the dungeons from the Count of Monte Cristo even though it is a work of fiction.

The birthplace of the builder of the Statue of Liberty is now a museum dedicated to his work.

A copy of the Statue of Liberty greets visitors to the birthplace of Auguste Bartholdi.

The oldest inn in England served brew to the crusaders.

A striking 500-year-old mansion provides an unexpectedly sublime home for live deer and a menagerie of exotic stuffed animals.

English Protestants once criticized this enormous private chapel for being too ornate.

The largest oak in England is said to have been the hideout of Robin Hood and his Merry Men.

Böttcherstraße's bells, extolling Nordic virtues and the great conquerors of the world.

A spitting ode to a German serial killer.

Ever-growing collection of devils in art.

The oldest funicular in Lithuania has been climbing this steep hill since 1931.

A memorial to the murdered Jews of Kaunas.

Beneath Kraków Old Town's main square lies a hologram-filled medieval market vampire graveyard wonderland.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

An underground city of salt.

The former Nazi Germany concentration camp stands as a museum to remember this dark chapter in European history.

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

A 19th-century artistocrat's mansion, turned into a library, hidden in a modern library.