A deadly ancient portal to the underworld.

A Lycian city of the dead carved into the hillside of Southern Turkey, complete with startlingly human touches.

A mysterious ancient cemetery with Roman sarcophagi and Lycian inscriptions.

Hidden just under the waters around this Turkish island are the ruins of a once great city.

This church houses the tomb—but not the remains—of St. Nicholas, the likely progenitor to Santa Claus.

This functioning parish church is also the site of many concert performances due to its wonderful acoustics.

The world's northernmost aquarium looks like it has fallen over.

The great polar explorer is remembered in this far northern town, where he embarked on his final expedition.

The world's most charming instant portrait studio also happens to be its smallest.

A much-loved sculpture depicting the hero of a 1956 anti-Soviet uprising.

A triumphant marble and bronze fountain depicting a 15th-century Hungarian king and his hunting party.

The metal leaves on this tree are engraved with the names of Holocaust victims.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

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

Eat the ultimate iteration of Portugal's most beloved pastry.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

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

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

The best place in the world to buy tinned fish.

The world's oldest bookshop still in operation.

One of the best-preserved medieval streets in Europe.

At Monet's beloved home you can still see the Japanese bridge, waterlilies, and weeping willows that were the subjects of some of his most iconic paintings.

The deepest underground city in Turkey was designed to protect 20,000 people behind massive stone doors.

In this historic region, homes and churches are carved into ancient volcanic rock formations.