We went to Spurn Point in East Yorkshire: go to Hull an keep driving for 45 minutes. On the way we found the monument in the pictures above. We had crossed the Greenwich Meridian. The north/south line on the Earth is obvious: it's the Equator. The east/west line isn't obvious and was set up by human choice. It runs through Greenwich in London because that's where the astronomers who did the work on it were based. Your distance east or west affects the time for things like sunrise and sunset. We would say that it was midday when the Sun was highest in the sky. If you fix your watch so that it says 12 noon when you are stood on the Greenwich Meridian, your watch will be showing Greenwich Mean Time or GMT. In Wigton, we are 3 degrees west of the line. 3 out of 360 degrees over 24 hours adds up to 12 minutes. 12 noon arrives here 12 minutes after London.
