Andrew Marr sets out to tell the story of humanity from the first migrations out of Africa to the twentieth century, filming on location across five continents. The series moves chronologically, covering the rise of early civilizations in Mesopotamia and Egypt, the spread of empires from Rome to the Mongols, the age of exploration, and the industrial and political upheavals that shaped the modern world. Marr narrates on the ground at sites tied to the events he describes, mixing walk-and-talk pieces to camera with dramatized reenactments and expert contributions to fill in periods where visual evidence is scarce. Rather than a strict list of dates, the series follows recurring threads such as trade, conquest, belief, and technology, showing how developments in one region repeatedly reshaped distant others. Marr's own argument runs through the whole series: that history is driven less by inevitable forces than by individual decisions and chance encounters, and he keeps returning to the people who made them.