We call our connections with family, friends, neighbours and classmates "social networks". Everyone is integrated into such networks. What would we see if we could look down on everyone's social networks like a bird from above? Would everyone be connected to everyone in some way? Or are there many individual networks, like islands in the sea? And why is the answer to such a question important at all?

Facebook, Twitter and Instagram are particularly good places to see and explore how people are connected to each other: Lukas is friends with Ida, Ida with Max, Max and Lukas with Leonie and so on. We can learn a lot from this about how social networks work. Scientists have also discovered that such networks can be compared with completely different ones, for example with our transport system with its many roads, railways and air links. You'll see: It's pretty exciting!