GlobalXplorer is the latest crowdsourced science project, this time in the service of preserving archaeological sites that are being looted. Participants scan satellite images for signs of looting, and mark sites off a map.
Once you sign in and pass a tutorial, you're ready to start. Telltale signs include pockmarks indicating two- to three-meter holes dug by looters. Here's some more background on the project by the founder, Sarah Parcak:
From the GlobalXplorer site:
So far, Dr. Parcak's techniques have helped locate 17 potential pyramids, in addition to 3,100 potential forgotten settlements and 1,000 potential lost tombs in Egypt — and she's also made significant discoveries in the Viking world and Roman Empire. With the help of citizen scientists across the globe, she hopes to uncover much, much more. This is just the beginning. With additional funding, Dr. Parcak aims to revolutionize how modern archaeology is done altogether, by creating a global network of citizen explorers, opening field schools to guide archaeological preservation on the ground, developing an archaeological institute, and even launching a satellite designed with archaeology in mind.