To preserve their rich stores of fish oil and meat, they created elaborately decorated pottery. And they built the world’s first known fortresses, perhaps to keep out aggressive neighbors.

With room inside for dozens of people and dwellings sunk almost 2 meters deep for warmth in Siberian winters, the fortresses were ringed by earthen walls several meters high and topped with wooden palisades. At some point, they were consumed by flame, a possible sign of early battles. And at least one set of structures was built startlingly early: 8000 years ago, 2000 years before the mighty walls of Uruk and Babylon in the Middle East and thousands of years before agriculture reached some parts of Europe and Asia