Far from the beaten track, this extraordinary passage tomb dates from 3000 BC and, like Newgrange, is aligned with the winter solstice. The mound is 19m in diameter; a passage leads to a large central chamber, from where three recesses branch off. Since its excavation in 1952, a pierced concrete roof allows natural light to illuminate the Neolithic carved stones. Collect the key from Mr Finton White (detailed directions to his house are posted on a sign at the tomb).
Parking is limited to the road. It's 18km south of Drogheda (35km north of Dublin).