Walls and fences are often built with the intention of security, security from another group of people, from crime, from illegal trades. But walls and fences only provide us with a feeling of security, which is different from real security. Even though they might make us feel safe, the structures themselves can’t protect us. Instead, they do something else: they separate. They create an "us" and a "them". They establish an enemy. Walls make us build a second wall in our head, a mental wall. And those mental walls slowly make us lose sight of all the things we have in common with the people on the other side. The other way around, mental walls can grow so strong that they encourage us to build, keep or strengthen physical walls. Physical and mental walls are closely interlinked, and one almost always comes with the other. It’s a constant cycle: physical walls empower mental walls, and mental walls empower physical walls until at one point one part falls away, and the cycle is disrupted.