We added another UNESCO stop on our way to the Giant’s Causeway, the Brú na Bóinne. The “open air tombs” were discovered here on accident around the 1700s and its contruction predates the pyramids, over 3.5K years ago (in the Neolithic period).
During the winter solstice light enters the tomb through a small and pinpoints a spot on the far back wall of the structure. Much like Stonehenge this structure is believed to have an array of astrological significance.