Good question – thanks! It’s because of the amount of sun light there is. People need pigment in their skin to protect them from being sunburnt (that’s why you get a tan – it actually protects your skin). But we also need some sun to go through – because we produce vitamin D in our skin and without vitamin D we can’t have healthy bones. So if there’s alot of sun where you live you have to be dark – to protect yourself. You’ll produce the vitamin D anyhow. But if there isn’t that much sun (like in Europe) you need to be lighter skinned.