Macabre astrological automaton clock dating to the late 1400s.

A church of bones, decorated with 40,000 human skeletons.

This narrow fjord-like bay is the largest ria in the Mediterranean Sea.

One of the best-preserved Roman amphitheaters is still used today, but for less brutal events.

A musical instrument played by the sea.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

This one-of-a-kind archeological site is home to strange prehistoric ruins, the original use of which is still a mystery.

This celebration of Latvia’s freedom and independence avoided demolition over half a century of Soviet occupation.

The reconstruction of this prominent building fulfilled a long-written command.

A black cat protests the City Guild in Riga's Old Town.

The fishing boats that moor in this small lagoon enter and leave through a tunnel to the sea.

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

A perfectly circular lake is formed by the crater of an ancient underwater volcano.

"Portugal's Stonehenge" is made up of nut-like stones aligned with the heavens.

A stunning 18th-century site where pilgrims ascend by a series of punishing stairs only to return via funicular.

A unique seaside cave where Aleister Crowley faked his own death.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

A 16th century chapel decorated with bones, skulls, and entire bodies hanging from the wall.

The geographical center of Budapest is marked with a 10-foot-tall stylized zero.

Inside the Šomoška National Nature Reserve exists a unique rock formation rarely seen in the world.

An industrial site turned into Hungary's most cherished natural wonder.

This hidden art nouveau gem was designed by an architect in search of a national style.

A museum dedicated to a secret military hospital hidden beneath a castle in Budapest.