A curious cave church carved into the face of a cliff.

These historic defenses ensured the city within would survive hundreds of years of occupations, sieges, and invasions.

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

These temples are among the oldest free-standing stone buildings in the world.

This unique building in the main square stands out among the city's typically Baroque architecture.

The floor of this spectacular Baroque sanctuary is covered in memento mori.

This spectacular dome managed to survive after being bombed in World War II, in an event known as the "Miracle of Mosta."

A statue erected in honor of the toadish nickname given to Jersey residents by the French.

Something's missing between the arcades of the Palazzo della Ragione in "the city of the three withouts."

Stare out over the lagoon and beyond from this 10th-century campanile on the island where the city of Venice began.

This bustling Italian plaza is built on the ruins of an ancient Roman amphitheater.

The only visible reminders of an elaborate engineering project that kept the tower from reaching the tipping point.

This Roman statue is missing a limb from when the Venetians stole it from Constantinople during the Crusades.

A whale rib was used to advertise the store by the arch that offered exotic goods from far away.

Thousand-year-old Viking runes adorn an ancient Greek lion at the entrance to the Venetian Arsenal.

The oldest botanical garden in the world that technically isn't the oldest.

A menacing statue of this mythical creature can be seen at the legendary site of the monster's lair.

A statue honors the children who fought Nazis in Poland.

A tribute to the Polish insurgents who fought in the failed attempt to end their city's Nazi occupation.

This Nazi ruin was the site where Hitler was almost blown up by a suitcase bomb.

This charming Latvian lane doubled as Baker Street on the Soviet Union’s version of Sherlock Holmes.

The oldest housing complex in Riga is a mini timeline of architectural trends.

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

Two stone columns flank the grand Venice square, but there were supposed to be three.