Dowth the Fairy Mound of Darkness is about the same size as Newgrange and Knowth ancient sites and was built in the same period over 5000 years ago before the pyramids or Stonehenge. It is one of the oldest structures on Earth and thought to have an astronomical purpose. Marie Moroney has been observing winter sunsets at Dowth since 1997. From the beginning of October to the end of February the sun sends its rays from the south-west into the chamber. As the sun appears progressively lower in the sky towards the winter solstice, the beam travels first over the sill stone, then