Walk into any archaeologist’s laboratory and you’re likely to see bags of broken pottery. Walk into Bárbara Arroyo’s laboratory in a warehouse on the edge of the ruins of Kaminaljuyú in Guatemala City and you’ll find bags containing millions of pottery sherds, stacked almost to the ceiling. Millions more sit in the vaults of the National Museum of Archaeology and Ethnology a few miles away. Outside Arroyo’s laboratory, she and her team have dumped thousands upon thousands more ancient ceramic scraps into a large hole. “They can’t take any more at the museum,” she says with a shrug, gesturing out a window at the overflowing pit