Newgrange and Knowth: A civilisation older than the pyramids

I had no idea that cavemen were such geniuses. Newgrange and Knowth, monuments older than the pyramids, are a testament to this. The sheer architectural brilliance it would have required to map out exactly where the sun would strike for the different position in the sky on one 365th of the year to mark the Winter solstice is amazing. How they did it back then, with no written language and no metals, rulers, or squares to build their buildings is just amazing. This single act of precision stunned me, especially when I was inside the structure and they showed what the solstice would look like at the end of the year. The design was so precise, in fact, that the ray of sunlight that penetrates the tomb once a year strikes to the left of the tomb, where 5000 years ago, it struck in the centre. The infinitesimally small movement of the axis of the earth over 5000 years has moved the beam about thirty centimetres from where it struck 5000 years ago. While Newgrange was built to mark the Winter solstice, Knowth was built with east-facing tunnels, which might mean it marked the equinoxes. Magic symbols surround the tombs, and one can even be used to tell the time, like a sundial.