In the wee hours of the morning in a lab in Amherst, Massachusetts, geoscience graduate student Rob D’Anjou sat looking over test results, a pot of coffee nearby. He’d been pulling long days to ...

In the late 1950s, archaeologists discovered a cave in the Rio Zape Valley of Mexico. There were ancient human remains in the cave dated to between 660 and 1430 A.D., many of which belonged to ...