added by archaeologs One of the largest and most splendidly decorated passage graves of the Boyne area of Ireland, c40 km north of Dublin. The mound has a diameter of 80-85 metres and is cl 1 metres high; it is surrounded by a kerb and an outer freestanding circle of stones, originally 35 in number, of which only 12 survive. The tomb has a very long passage, 19 metres in length, and built of orthostats; the chamber is cruciform in plan and roofed with a magnificent corbelled vault. Many of the stones of the chamber, passage and kerb are decorated with pecked geometric designs, characteristic of Irish passage grave art. The central chamber was illuminated at dawn on the winter solstice through a gap left above the entrance — the earliest documented astronomical orientation yet recorded in the megalithic monuments of northwest Europe. Radiocarbon dates indicate that the tomb was built in the mid-3rd millennium be (late 4th millennium bc).
The Macmillan dictionary of archaeology, Ruth D. Whitehouse, 1983