If we ultimately uncover Genghis Khan's tomb, we may have outer space and about 10,000 volunteers to thank. As Smithsonian recounts, legend has it that the location of the Mongolian warrior's tomb was safeguarded by soldiers who murdered the tomb builders and were then killed themselves. University of California-San Diego scientist Albert Yu-Min Lin has been on the hunt for this "needle in a haystack," and since 2010, he's had some help: Under his Valley of the Khans Project, volunteers were able to visit a National Geographic website, sift through high-res images of Mongolia taken by orbital satellites, and flag any features they spotted. Except no similar burials have been uncovered in Mongolia, so "the appearance of the needle is undefined." In a paper published Dec. 30 in PLOS One, Lin reports on what was accomplished in the first six months.
Some 10,000 volunteers spent 30,000 hours (that's 3.4 years) examining roughly 2,300 square miles (two times Yosemite's size) that had been tiled into 84,183 images. They were asked to tag any feature they spotted as a road, river, modern structure, ancient structure, or other. Participants tagged 2.3 million sites, and the researchers used "consensus, defined by kernel density estimation, to pool human perception" for features with potentially ancient origins. The field team explored 100 of those and positively identified 55 sites with archaeological significance (no Genghis Khan tomb, sadly), including Bronze Age burial mounds. The researchers ask: Could archaeologists have found these themselves? Their answer: A ground search would have been "prohibitive," and a scan of the images would have required an archaeologist to scan through 20,000 screens. (A remarkable tomb was found in Egypt recently.)