This gem is often wrongly overshadowed by the larger, newer Metropolis church in Athens.

This small 16th-century church in Athens is almost entirely surrounded by a modern building.

The ruins of an abandoned medieval city where the last Byzantine emperor was crowned.

A cave network located at the southernmost tip of mainland Greece was once believed to be an entrance to Hades.

This wrecked ghost ship has been rusting on a Greek beach since the 1980s.

The top of the holy mountain for the ancient Spartans looks like a pyramid—is it man-made or a natural phenomenon?

The historic tower houses of this nearly abandoned Greek town have been compared to the spikes on an iguana's back.

Legend has it the lovelorn tears of a princess and a shepherd boy formed the blue and green twin lakes in the Azores archipelago.

One of few vertical lava tubes in the world accessible by foot.

The doodles of a genius line the walls of a secret room under the Medici Chapel, where they were hidden for nearly 500 years.

This narrow Ghent alleyway is an officially sanctioned street art tunnel.

Each time a baby is born in Ghent, these streetlights flash in silent celebration.

This fairytale castle was built as a show of power but was nearly torn down thanks to its history of torture.

An unsettling sculpture of a boy hanging out in a street in Ghent has been baffling visitors for years.

Beautiful Austrian natural history museum with carved ceilings and row after row of ancient taxidermy.

A glimpse into the festive and private lives of medieval Europe.

The solemn exterior conceals an opulent interior of this 17th century church.

An exquisite Baroque church in Vienna's old town.

A spherical "micro-nation" in the heart of Vienna.

Vienna's giant wonder wheel had a starring role in one of the greatest noir movies of all time.

One of the most notable figures in the Wurstelprater’s history is often assumed to be a fictional character.

Baroque celebration of the end of the Great Plague of Vienna.

On a winding Vienna side street, one museum has turned their windows into a monument to history’s peace-minded heroes.

Legends surround an ancient tree trunk riddled with nails for good luck.