I’ve seen the pyramids near Cairo and Mexico City. They are immense. The endeavor behind their construction if it wasn’t for the fact of their existence is inconceivable. When I saw them the thought intruded both times - how many lives were lost in their construction? Equally, impressive is the mental processes that created their shape and worked out the mathematical calculations necessary for them to be built in that shape. It was not done by random. Probably the impulse for mathematics arose from studying the sky. Early hunters, navigators, farmers, each had different lessons to learn, indeed had to learn. In North America the Plains Indians learnt that until certain stars appeared in the night sky it was too soon to depart for their seasonal summer hunting grounds. The mighty Giza pyramid near Cairo is aligned to the pole star. The seasons can be read from its shadow. The Polynesians colonised the Pacific with their star maps. Humanity’s capacity for achievement continues to amaze me. Unfortunately, there is also its capacity for destruction.