Walls have been our direct response to threat for centuries and over the last 20 years the global desire for walls has been growing. We have more border barriers now, in the age of internet and globalisation, than at the end of the second world war. But the effects of walls on societies go far beyond protection: Walls separate by establishing an “us” and a “them”; they make us build a mental wall. The talk focuses on the link between physical and mental walls, and shows an example on how to overcome the mental barrier again.