Carrick Roads is one of the deepest natural harbours in the world — a drowned river valley carved at the end of the last ice age, now full of silvery water, yachts, and the ferries that stitch Falmouth, St Mawes, Mylor, and Flushing together. The Fal, Penryn, and half a dozen smaller creeks all empty here. Sheltered by Pendennis and St Mawes Castles at the mouth, Carrick Roads has been anchorage to merchant fleets and royal warships alike. An aerial view shows a branching silver tree of water in the green Cornish landscape.