Finland's oldest astronomical observatory once played a crucial role in seafaring and timekeeping.

A subterranean house of worship carved right out of the bedrock.

This lucky bronze frog was gifted to Madrid by a casino.

This sweet-toothed bear searching for snacks has been a symbol of Madrid for decades.

A stone slab in Madrid marks the point from which the distances of Spain's national roads are measured.

On a cornerstone of the City Museum is the head of a monstrous serpent stolen from an Aztec pyramid 400 years ago.

Several times a year, during low tide, two pairs of historic train tracks are revealed on this New Jersey beach.

The rusting remains are visible sticking out of the waters of the Delaware Bay.

World War II bunker still standing on the New Jersey beach.

In the woods of New Jersey lie the ruins of a munitions village abandoned after World War I and the remnants of a 1920s wooden racetrack.

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

Inside this Krakow church, an explosion of psychedelic color.

Real bones which are said to have belonged to a Polish dragon.

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

The first museum in the world devoted to sexual gadgetry.

A bust of Franz Kafka spins in pieces, reflecting the writer's inner torment.

Macabre astrological automaton clock dating to the late 1400s.

The slender brass strip in Prague's Old Town Square was used to tell time from 1652 to 1918.

Synagogue built from the stones of Solomon's temple contains the golem of Prague.

A surreal statue honoring Prague's favorite literary son.

Medicinal spa created with the discharge from a geothermal energy plant.

The fastest way to send a message before electricity was invented.

A small church in Uppsala hides the grave of a renowned 18th-century astronomer.

Ancient burial grounds of the wealthy.