This enormous ancient series of hilltop tombs is set spectacularly overlooking the Bay of Morlaix, on the edge of the modern-day village of Plouezoc'h, 10km north of Morlaix. Built between 4500 and 3900 BC, the cairn measures 75m and comprises two sets of tombs, built in successive eras but attached to each other. You can walk through the centre of the cairn, where it was once, amazingly, used as a source of stones in the 1950s.
The cairn today remains an imposing and magnificent sight. A joint ticket with the Château du Taureau gets you a reduced fee for both.