This natural sea cave hides a small wonderland of natural turquoise beauty.

A well-preserved network of cavernous tunnels have spent silent centuries removing Toronto's waste.

A 98-room castle in the middle of Toronto that bankrupted a 19th century electricity multimillionaire.

One of Canada's most incredible rare book collections holds hundreds of thousands of gorgeous tomes that the general public can touch.

Secret refuge and museum of the Duke of Florence.

The famous sculptor left his mark on this Italian wall in an internationally protected example of street art.

Over 50 exquisite hand-painted Renaissance maps decorate a Medici storage room.

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

A large grotto built in the 16th century amidst Florence's famous Boboli gardens.

The middle finger of modernity.

A rather vulgar example of the transition from Latin to the Italian vernacular.

This park on the outskirts of Rome boasts two ancient Roman aqueducts and a medieval tower.

The ruins of an abbey believed to have been founded by Charlemagne in the 9th century.

The best preserved Paleochristian basilica in Rome hides a number of oddities and secrets.

A treasure trove of Renaissance-era funerary art in a Roman church built on top of Nero's grave.

Roman-era ships unearthed...

Charles Dickens was not a fan of the ghastly wall dressings in this 6th century church.

This beautiful park on the outskirts of Rome protects the ruins of two colossal ancient aqueducts.

This hill made entirely of ancient Roman jars was simply a garbage dump to the people of the time.

The Pope’s secret escape route.

One of seven Jewish catacombs in Rome and one of only two open to the public.

A Nesting Doll of Churches.

Jesus' footprints and the first catacombs in the world.

2300-year-old Roman road connecting the empire.