Sierra de Atapuerca Junta de Castilla y León

The gently rolling hills known as the Sierra de Atapuerca in northern Spain hide a complex system of large limestone caverns. Openings into the caves dot the hillsides, and for nearly one million years, these cave entrances have provided shelter for humans as well as animals. Over the millennia, the inhabitants of Atapuerca left behind an extraordinary fossil record that scientists are just beginning to unearth.

The story of Atapuerca’s early residents might well have remained hidden forever. But in the 1890s the Sierra Company, a British firm, began to build a railroad through the region. During construction, workers removed a portion of one hillside—and exposed the sediment-filled cave now known as Gran Dolina, one of the most important archaeological sites in Europe. Atapuerca is also home to a second major site, Sima de los Huesos, or the Pit of the Bones. Together, Gran Dolina and Sima de los Huesos have revolutionized our understanding of the early inhabitants of western Europe.