Newgrange, a Neolithic passage tomb that is older than the pyramids in Egypt, is located in the Boyne Valley, Co Meath. It features a 19m-long passage that leads into a chamber with three alcoves.

A passage tomb is a burial chamber usually set within a circular mound that is accessible via a passage – those at Newgrange and Slieve Gullion are estimated to be about 5,000 years old.

The solar alignment of the passage tomb at Newgrange to face the rising sun on the winter solstice was originally rediscovered by Prof Michael J. O’Kelly in 1967. Other researchers have since ...