What makes things sticky? Listener Mitch from the USA began wondering while he was taking down some very sticky wallpaper. Our world would quite literally fall apart without adhesives. They are almost everywhere – in our buildings, in our cars and in our smartphones. But how do they hold things together? To find out, presenter Marnie Chesterton visits a luthier, Anette Fajardo, who uses animal glues every day in her job making violins. These glues have been used since the ancient Egyptians –but adhesives are much older than that. Marnie speaks to archaeologist Dr Geeske Langejans from Delft University of Technology about prehistoric glues made from birch bark, dated to 200,000 years ago. She goes to see a chemist, Prof Steven Abbott, who helps her understand why anything actually sticks to anything else. And she speaks to physicist Dr Ivan Vera-Marun at the University of Manchester, about the nanotechnologists using adhesion at tiny scales to make materials of the future. Presented by Marnie Chesterton. Produced by Anand Jagatia for BBC World Service This episode was originally broadcast on 2nd October 2020