In this episode Steven chats with an old friend, professor of Geographical Information Science at UCL, Muki Haklay. Muki is one of the early adopters of combining geography with computer science, and one of the eariest supporters of OpenStreetMap. For the past ten years he has been focusing on extreme citizen science. There are a number of programs and apps that allow people all over the world to contribute geographical and environmental data. His team of 20 researchers work with indigenous communities on developing tools that can be used by anyone, even those who can’t read or write, allowing for more access to relevant data about their own communities. Steven and Muki discuss the benefits and drawbacks of citizen science as it becomes more common.