The roof of this ancient mausoleum is made from a single Istrian stone weighing a massive 230 tons.

Psychoanalyst Carl Jung reported a paranormal experience after visiting this mosaic-lined Roman baptistry.

An incredible mosaic-lined monument said to have held the remains of an ancient Roman empress.

This 6th-century church has the largest and best-preserved collection of Byzantine mosaics outside Constantinople.

Italian poet Dante Alighieri is entombed in this small mausoleum in Ravenna, and his hometown of Florence has never been too happy about it.

Filled with goldfish swimming in a shallow pool of sea water, this ancient crypt is more wishing well than burial site.

The legendary luxury train passage is commemorated with a charming museum inside its former eastern terminus.

This historic black and white monastery is one of Bulgaria's architectural jewels.

This building has two facades of clashing architectural designs.

Sofia's legislative center is continuously reinventing itself.

A meow-velous tribute to a beloved street cat, made famous on the internet.

A gorgeous, Gaudí-esque stairway constructed in the city of Istanbul by a prominent Jewish family.

A vast Communist-era exhibition space in the Bulgarian capital.

A striking symbol of the Bulgarian capital.

Underneath this Byzantinian church lies a necropolis filled with ancient tombs and the ruins of previous churches.

"Holy Wisdom" overlooks the city that became its namesake.

Despite attempts by local police to discourage it, Beatles-inspired graffiti has been a means for artists to air grievances for decades.

A bust of Franz Kafka spins in pieces, reflecting the writer's inner torment.

Next to the Leaning Tower of Pisa is a cemetery home to ancient sarcophagi and disturbing murals.

Five candy-colored villages on the Italian Riviera.

The bomb-ravaged remains of of a colossal Neptune.

Massive galleon from a box-office bomb docked in Genoa.

Byzantine emperors ruled, lived, and died in this 13th-century palace-turned-museum.

Taking the subway here means doing so over a bridge located in the middle of an estuary.