Peruvian workers clean graves containing a trove of pre-Inca artifacts in Ferrenafe, Peru, Tuesday, Nov. 21, 2006. Archaeologists in northern Peru said Tuesday they have unearthed 22 artifact-rich graves containing a trove of pre-Inca artifacts, including the first 'tumi' ceremonial knives ever excavated scientifically. The more than 900-year-old tombs were found next to a pyramid in the Pomac Forest Historical Sanctuary, about 680 kilometers (420 miles) northwest of the capital, Lima. They are from the Sican culture, which flourished on Peru's northern desert coast from A.D. 750 to 1375. (AP Photo/Martin Mejia) Archaeologists said Tuesday they have unearthed 22...