A mysterious green rock discovered high in the Pyrenees suggests that prehistoric people maintained a high-altitude copper mining camp in Spain for more than four millennia, according to archaeologists. The cave was filled with layers of green mineral fragments and abundant pieces of charcoal, which suggests that people repeatedly returned to the seasonal camp for generations.
Archaeologists discovered the cave at around 7,333 feet (2,235 meters) above sea level in the Spanish province of Girona, near the mountainous border with France. Inside, the researchers found human remains, animal bones, broken ceramic vessels and prehistoric fireplaces — all evidence that people used the cave for more than 4,000 years. They also uncovered close to 200 pieces of the mysterious green rock that was not naturally present in the cave.
