Newgrange is a 5,200-year-old Neolithic passage tomb in County Meath, Ireland. It is older than the Egyptian pyramids and Stonehenge and is known for its spectacular astronomical alignment during the winter solstice.
Every year on December 21 (and the mornings surrounding it), the rising sun shines directly through a 'roof box' above the entrance, illuminating the inner chamber for 17 minutes. Built around 3200 BC with approximately 200,000 tonnes of stone, partly transported from the Wicklow Mountains and the Mourne Mountains.