A giant calendar? A cathedral to unknown gods? Or something more macabre? For centuries, archaeologists have argued over why and how Stonehenge was built. Now, a team of experts is attempting to reveal why this stunning and mysterious monument was created and why its remote location was chosen. Follow them as they comb a vast prehistoric settlement and perform forensic examinations in order to unlock the secrets of this 4,500-year-old prehistoric structure.

In 2004, a grim discovery was made at an excavation site in the historic city of York, England: a mass grave containing dozens of young male skeletons, all ritualistically buried. Archaeologists believe they may have unearthed a cemetery of battle-hardened gladiators. If they're right, it will rewrite the history of the Romans in Britain. Join host Adam Mastrelli as we study the bones and remains found at the site and analyze their DNA in an attempt to reveal new insights about this dark side of the Roman Empire.