National Museum of Natural History
10th St. & Constitution Ave., NW
On view for the first time is the Smithsonian's own crystal skull. The artifact arrived in the mail in 1992 with an unsigned letter claiming it was Aztec. To learn of its true origin, museum anthropologist Jane MacLaren Walsh and several colleagues used the latest scientific technology—a scanning electron microscope (SEM)—and discovered it was carved from milky quartz using modern stone-carving tools.