An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.

Dedicated to a synagogue that was destroyed after having survived World War II.

Brass plaques embedded in pavement preserve the memories of those who lost their lives at the hands of Nazis during World War II.

This irregularly shaped sea fortress has defended not one but three different sovereign states.

This daunting 1st century fortress was purportedly the site of one of the most dramatic revolts of the Jewish-Roman wars.

Descend 2,030 years into the past in an ancient tunnel built to support Jerusalem's most famous wall.

The home of the Dead Sea Scrolls is an abstract modernist dream.

The bluer than blue waters in these natural Israeli caves are reached via the world's steepest cable car.

On the wall of this medieval walkway, a symbol of the Spanish Inquisition.

Dunk your churros in rich hot chocolate on the city’s old “Chocolate Street.”

Heralded as the world's first theater, these ruins are often overlooked as they reside in the shadows of the Acropolis.

Few other hotels can rival the grandeur of the Castle in the Rockies.

Local legend says Isaac Newton built this footbridge without any screws, bolts, or nails.

The Cambridge pub where Francis Crick announced that he and James Watson had discovered the DNA double-helix.

Numberless clock creates a meal of time for the dreaded, insectile Chronophage.

The de facto symbol of Copenhagen is this bronze fairytale which cannot seem to keep its head for very long.

Copenhagen's celebrated theme park and gardens.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

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

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

The beautiful baroque library of the Hapsburg empire.

This community on a small Venetian island has taken to painting their houses in bright neon hues.

This Venice bookstore has resigned itself to constant flooding by keeping its books in bathtubs and boats.

The last remnants of a massive medieval wall that once encompassed the city of Berlin.