1.2 Million Years Ago
In Kenya's Great Rift Valley, mountains sandwich a lake. People bring rocks from the mountains to the lake where people's largest, longest project ever takes place: a tool-making factory or perhaps a religious site centered around hand axes that's used consistently for a million years. For reasons we can only guess, they brought heavy rocks down from the mountains to the shores of the lake six miles away.
Despite one million years of continued use, homonid bones have never been found at Olorgesailie.

350,000 Years Ago
When they light the fires, that's when the stories start. Maybe an older woman shares about her mother. Maybe a young man spins a tale of today's hunt, laughter and gestures growing wilder as the coals burn hotter. This is where culture is born, where we stretch our fledgling wings of empathy and community as a species. The first is safe from animals, warm from the cold. You have no choice but to listen to those who join you there.
In Olorgesailie, the axe-makers still bring their rocks from the mountain to their workshops.
Across the continent, mammoths herd their young away from the weapons of hunters.

5,000 BCE
It is 5,000 BCE in what will one day be called Romania, and the village is on fire. They'd left days ago, staying nearby to complete the work of packing hay around the bases of all the structures. Then one of the elders coaxed a spark onto a torch and touched the torch to the piles of dry grass and before long the smoke stung the eyes of the villagers standing on the hill top, watching. For nearly three thousand years, ten cultures in a widespread area of Eastern Europe intentionally destroyed their settlements with fire about once a generation. The fires burned so hot that archaeologists haven't fully recreated the burns.