Bay of Morlaix: The Barnenez Cairn, the Bull Fort and Roscoff's Onion Johnnies

Required Activities

• Walk round the Cairn of Barnenez, 75 m long and 28 m across at its widest, and count the entrances to its eleven passage graves, then look at the quarried west face, where a contractor's excavator cut open chambers A to D in the spring of 1955 and left the inside of the cairn on show

• Take the boat from the plage du Kelenn at Carantec or the port du Diben at Plougasnou to the Château du Taureau, the fort built out at sea between 1690 and 1745 to Vauban's plan, and find the vaulted 'salle de discipline' where the Communard Blanqui, locked up here on 17 March 1871, wrote L'Éternité par les astres

• Visit the Maison des Johnnies in Roscoff, on the onion sellers who from 1828 crossed to England each year between late July and Advent, and find what it holds on the wreck of the Hilda on 17 November 1905, which drowned many of them, then buy Roscoff pink onions, a variety brought from Portugal in the 16th century and now protected by its own appellation

• Walk the Jardin exotique et botanique de Roscoff, 1.6 hectares holding about 3,350 plants from Australia, New Zealand, South Africa, South America and the Canaries, and climb the 18 m granite outcrop of Roc'h Hievec at its centre for the view over the bay