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

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

Go inside to really appreciate this 500-year-old technological masterpiece.

Venice's "Island of the Mad."

Legend has it that this bronze orb, which sat atop an ancient Egyptian obelisk, once held the ashes of Julius Caesar.

A monumental fountain in Rome features a large statue of Moses that has been criticized for centuries.

These hut foundations are believed to be the residence of Romulus, founder of Rome.

Its interior is adorned with some of the best examples of early Christian mosaics.

One of Catholicism's four major basilicas has a series of papal portraits that are said to predict the end of the world.

The ruins of the largest gladiatorial school in Rome are largely hidden under modern streets.

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

A Nesting Doll of Churches.

Jesus' footprints and the first catacombs in the world.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

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

Da Vinci's equestrian statue, 500 years in the making.

This trail was once used to smuggle cigarettes, sugar, and other black market goods between Italy and Switzerland.

What appears to be an ancient Roman temple is actually a Catholic church.

This splendid tomb may look fantastic, but there's nothing in it...

A memorial for a young woman and her ghost, which are claimed to have caused countless deathly shipwrecks.

Birthplace of the "Cat in the Cradle" and a cluster of iconic, original windmills that let the Dutch tame the seas.

One of Amsterdam's narrowest houses is located right across the canal from its widest.

This museum housed in a former brothel explores the past and present of sex work in Amsterdam.