Famously misunderstood wonder of the ancient world

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

Known for centuries as the famous Roman emperor's burial place, this monument is actually something else.

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

Rome's first modern graffito is all that is left of a peaceful protest from the 1970s.

This ancient Roman arch misled treasure hunters for centuries.

Inside this McDonald's you can dine on your Big Mac and fries next to a 2,500-year-old Roman wall.

Ancient ruins hidden underneath a modern luxury hotel.

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

A detailed pachyderm supports Rome's smallest Egyptian obelisk.

Brass cobblestones mark the places where individual Holocaust victims were taken from their homes.

The spot where the fascist dictator made some of his most famous speeches including declaring war on Britain and France.

Rome's ancient Etruscan rival, now a park full of ruins.

A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.

This Roman arch marks the location of an ancient gate at one of the Seven Hills of Rome.

At the crypt of St. Mary of Eulogies and the Dead you are left alone to ponder mortality among piles of skulls.

The yawning maw of this pagan visage is said to bite off the hands of liars.

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