With its 365 islets that appear and disappear with the tides (52 are visible at high tide), the Archipelago of the Chausey Islands is the largest in Europe. Its islands have largely been stripped of their blue granite that can be found in numerous buildings in Granville, Saint-Malo, and Mont-Saint-Michel. The rock of the Chausey Islands was born 540 million years ago with the Cadomian chain that then culminated at 13,123 ft (4,000 m) and generated granite throughout the Massif Armoricain. Traces of Neolithic life are visible in the mudflats north of the Sound, a channel running along Grande Île.