It is the largest bay on the Atlantic coast of the Americas, pivotal in the history of prehistoric, historic, and contemporary United States. Its tributaries drain a gigantic portion of the eastern U.S., including the Potomac River, home to Washington, D.C. Its fisheries have been depleted, its oyster and clam industries much reduced, and rising seas threaten its shores. Still, hardy residents cherish the bay and their efforts are restoring some of its ancient productivity.