The La Brea Tar Pits in Los Angeles are one of the world’s richest Ice Age fossil sites, formed where natural asphalt (tar) has seeped to the surface for tens of thousands of years. These sticky pools acted as prehistoric traps: an animal would wander in, become stuck, and struggle. That movement attracted predators and scavengers, who were then trapped in turn. Over time, this created a dense fossil deposit representing an entire ancient ecosystem—mammoths, mastodons, saber-toothed cats, dire w