There is a 5,000-year-old Irish passage tomb in the Boyne Valley
The Newgrange passage tomb in County Meath, Ireland, is one of the oldest known examples of a megalithic structure in Europe. Built around 3,200 BC, it predates Stonehenge by over 600 years. The tomb's unique feature is its roofbox, which allows a beam of sunlight to illuminate the interior chamber for 17 minutes on the winter solstice. Archaeologists have confirmed the age of the structure through radiocarbon dating and other scientific methods.