Fire up your imagination, and buckle your seat belt. Archaeologist Breck Parkman is sweeping us back 18,000 years to the peak of the last Ice Age.

Deep winter had frozen so much ocean water into glaciers that sea levels dropped by 400 feet. The “California Serengeti,” as Parkman christened it, stretched from Monterey to Mendocino. This vast fertile plain, thatched with grasses and tree-lined streams, “was probably the most spectacular place in the world for wildlife. Think of thousands of animals moving together, living together, feeding together, sometimes feeding on each other.  It would have blown our minds.”