With the help of a team of experts and the latest in 3-D scanning technology, Alexander Armstrong, along with Dr Michael Scott, explores the hidden underground treasures that made Rome the powerhouse of the ancient world.

Rome. The heartland of the greatest empire of antiquity. We are familiar with the Forum, St. Peter's Basilica and of course the arena of death that was the Colosseum. But what lay underneath? In this one-off documentary, Alexander Armstrong explores the underground world of the most powerful city in the Ancient World.—Tom Daly