In the surprisingly bustling field of prehistory, it’s always risky to try to establish that anything was the earliest of its kind. Nonetheless, Malta’s ancient temples may be the world’s oldest free-standing stone monuments. Constructed about 6,000 years ago, these massive structures conceal the answers to many questions about early human civilization. In her slide-illustrated Smithsonian Associates lecture, “The Mysterious Prehistoric Temples of Malta,” Georgetown University art historian Mariana Carpinisan discusses the complexes and many sculptures found in them. The latter, which mostly feature female figures, are among the possible evidence for the “goddess” religions that some archaeologists believe were central to early civilizations. At 6 p.m. at the Hirshhorn Museum & Sculpture Garden’s Ring Auditorium, 7th & Independence Ave. SW. $13. For reservations call (202) 357-3030. (Mark Jenkins)