I’ve looked at maps all my life, but never noticed that it gets dark earlier in the South East in summer than in the North West. Of course I know the Earth is tipped at an angle, something like 22° and I know that at the equator day and night are about the same length and that sunrise and sunset are about 6pm. But I hadn’t noticed the angle that the terminator of day and night is at.

As we are on the Greenwich longitude line I assumed the shadow would run straight up and down the globe. But of course it can’t be if the Earth is tipped. That also explains why we have seasons in the North and South hemispheres.