A mega factory is a modern invention–wrong–the ancients were the first to build these thousands of years ago. What was the incredible 16 wheel Roman automated factory in the south of France which could feed 12,500 people a day? How did the ancient Egyptians produce hundreds of vehicles of war every month? How did the Romans forge enough iron to equip an army, and mine enough gold to keep an economy afloat? With today's technology, this would be achievable, but how did the ancients do this thousands of years ago? We reveal the impossible ingenuity and techniques that made it possible for the ancients to have "Mega Factories" of their own.