Lomekwi 3 is the name of an archaeological site in Kenya where ancient stone tools have been discovered dating to 3.3 million years ago, which make them the oldest ever found. In July 2011, a team of archeologists led by Sonia Harmand and Jason Lewis of Stony Brook University, United States, were heading to a site near Kenya's Lake Turkana near where Kenyanthropus platyops fossils had previously been found. The group made a wrong turn on the way and ended up at a previously unexplored region and decided to do some surveying. They quickly found some stone artifacts on the site, which they named Lomekwi 3. A year later they returned to the site for a full excavation. Harmand presented her findings at the annual meeting of the Paleoanthropology Society on April 14, 2015 and published the full announcement and results on the cover of Nature on May 21, 2015. Around 20 well preserved artifacts have been dug up at Lomekwi 3 including anvils, cores, and flakes. An additional 130 artifacts were found on the surface. In one instance, Harmand's team was able to match a flake to its core, suggesting a hominin had made and discarded the tool at the site. The tools were generally quite large – larger than the oldest known stone tools, recovered in the Gona area of the Afar Region of Ethiopia, in 1992. The largest weighs 15kg, and may have been used as an anvil. According to Harmand, it appeared that the tool makers had purposely selected large, heavy blocks of strong stone, ignoring smaller blocks of the same material found in the area. She ruled out the possibility that the tools were actually natural rock formations, saying "The artifacts were clearly knapped and not the result of accidental fracture of rocks". Analysis suggested the cores had been rotated as flakes were struck off. The purpose of the tools found at Lomekwi 3 is unclear, as animal bones found at the site do not bear any sign of hominin activity. This is the greatest expression of late Neogene technology in human evolutionary history.