A dark, narrow tunnel that leads to a charming lake and waterfall.

This whimsical stacked cabin looks like something out of a children's book.

Structure built from the skulls of vanquished foes.

The tunnel's elegant proportions keep you snug with no claustrophobia freak-out.

Hamburgers are intensely proud of their tunnel beneath the river.

This psychedelic tourist trap is a leisurely descent into madness.

You've probably seen these distinctive orange-tiled columns on the big screen.

The non-native bovine herd was brought in to help conserve these Berlin wetlands.

This Berlin island is home to a flock of free-roaming peacocks, as well as a historic ivory folly.

A 12th-century fortress containing some of Berlin's oldest buildings.

600 stumps, branches, and trunks of different shapes and sizes.

This spooky statue sits outside a famous Prague theater.

The first museum in the world devoted to sexual gadgetry.

Ever-growing collection of devils in art.

A century-old prison in the heart of Vilnius is now a lively bar, dance club, and artist residency.

The Frank Zappa fan club erected this monument to their prog-rock hero to mark a new era of post-Soviet Lithuania.

The largest coin pyramid in the world is a carefully balanced stack of over 1,000,000 pieces.

Legend has it that Napoleon Bonaparte fell in love with this Gothic church.

A 15-foot-tall statue of the head of the Sopranos family greets passengers at a train station in southeastern Lithuania.

A hidden tunnel of bones in one of Malta's oldest churches.

Thousands of well-dressed mummies below a monastery.

Haunting graffiti left by prisoners of the Spanish Inquisition.

This uncanny fresco celebrating the "triumph of death" was split into four pieces to be moved to another museum.

When the river dries up, these stones start talking.