Bayou Sauvage National Wildlife Refuge encompasses 23,000 acres of fresh and brackish marsh within New Orleans and is the largest urban wildlife refuge in the United States. Its wetlands, bayous, lagoons, forests, and chenieres support both coastal and inland species, including fish, alligators, marsh rabbits, and 340 bird species, with waterfowl numbers reaching 75,000 in cooler seasons. Much of the refuge lies inside hurricane-protection levees, linking it to an abandoned plan for a vast new community once proposed here under several names. Unused interstate interchanges built for that unrealized development still mark how differently this part of New Orleans might have evolved.