In early 1916, the legendary Yale University archaeologist Hiram Bingham III completed his third and final expedition in southern Peru. He shipped home 74 boxes of artifacts from Machu Picchu, a spectacular site in the Andes that is believed to have been the last major settlement of the Inca empire. Those boxes were supposed to be on temporary loan and sent back to Peru by July 1917, according to the government decree that authorized their export. But toward the end of 1916, Bingham, who would soon be pulled into service as a pilot in World War I, began to worry that he would not have time to study the artifacts. In a letter to a colleague, he confessed that he had thought about cheating on the deal and let the Peruvians "whistle for it." The Peruvians are whistling for it now. Arguing that Yale improperly holds thousands of objects from all three of Bingham's Machu Picchu expeditions, the government of Peru filed a federal lawsuit against the university in December, just over a year after the parties appeared to have settled the dispute. Yale now has moved to dismiss the case, saying that Peru filed in the wrong court and that its claims would be "stale and meritless" in any venue. Peru must respond by April 20. Museum directors and archaeologists around the world are watching the case with intense interest. A victory for Peru, some believe, might encourage other nations to try to take back artifacts that are now valuable parts of collections. Few observers expect the Machu Picchu lawsuit to move very far toward trial. Most say they expect Peru and Yale to reach a final negotiated settlement sooner rather than later. But a peace treaty has seemed in sight before: In September 2007, Peru and Yale announced a resolution to the dispute--only to see it collapse under pressure from Peruvian activists. As in other conflicts about antiquities, scholarly inquiry, and national patrimony, passions about Machu Picchu can run very high.