St Malo rooftops

D#2, Mabel and I spent most of the day wandering round the quaint old part of St Malo - I loved it! Down at street level were the typically French shops, cafés and crêperies - extra 1 - while walking round the ramparts offered interesting views in every direction. I liked the ancient holey roof in the main blip that looked like fish scales.

Most of the other extras reminded me of the book I've just finished : the beach Marie-Laure loved to visit with Madame Manec; the house at No 4 rue Vauborel where they lived; and the island Fort National where Étienne was incarcerated.

The other extra is of the huge tree trunks on the beach that had us puzzled. Why were they there? What purpose did they serve? They stand right in front of the high walls of the castle. Suggestions, please?