Er-Grah Tumulus
The Er-Grah tumulus is 140 metres (460 ft) long. It was probably originally constructed in the fifth millennium BC as a cairn, which was extended in both directions. A pavement surrounded the stepped structure. The capstone indicates that the monument was completed at around 3,300 BC. According to A. W. R. Whittle, "In front of the south facade of the primary phase of the long cairn of Er Grah, close to where the menhir Brise originally stood...a pair of domesticated cattle were found in a pit. Radiocarbon determinations suggest a date in the late sixth and early fifth millennium BC."
Read more about this topic: Locmariaquer Megaliths