Calico Early Man Site, Master Pit 1, in the Mojave Desert of southern California, USA. The Master Pit sections of the Calico Early Man Site are where items were found resembling stone tools. The items date from around 200,000 years ago, during the Pleistocene. Some scientists argue that the objects were made by humans, while others argue that they were produced by natural geological processes. The theories are controversial due to uncertainty and disputes over the exact nature of the finds. The site is near Barstow, California. Photographed in June 2012.