11. Lighthouses

From the earliest known lighthouses, such as the Pharos of Alexandria, one of the Seven Wonders of the Ancient World, to modern-day automated buoys and solar-powered lantern rooms, this history of lighthouses is rich with personal stories of lighthouse keepers, daring construction efforts, and ingenious optical discoveries. Today, as lighthouses are usurped by more efficient aids to navigation, these elegant structures are being converted to bed-and-breakfast inns and environmental retreats.