Professor Mary Beard looks beyond the stories of emperors, armies, guts and gore to meet the everyday people at the heart of Ancient Rome's vast empire. In this programme, Mary asks not what the Romans did for us, but what the empire did for Rome. She rides the Via Appia, climbs up to the top seats of the Colosseum, takes a boat to Rome's port Ostia and takes us into the bowels of Monte Testaccio. She also meets some extraordinary Romans: Eurysaces, an eccentric baker, who made a fortune out of the grain trade and built his tomb in the shape of a giant bread oven; Baricha, Zabda and Achiba, three prisoners of war who became Roman citizens; and Pupius Amicus, the purple dye seller making imperial dye from shellfish imported from Tunisia. This is Rome from the bottom up.

Of the four elements, air is the most elusive because we can't see it. There's something very magical about it. One of the ways we transform food is by getting air into it. Think of the soufflé, think of the loaf of bread. These things are elevated by the fact that they now contain air. They're ethereal. Visit food labs and Moroccan fields as Michael Pollan delves into the science of bread-making and the nature of gluten.