Biscayne National Park protects the larger portion of south Florida's Biscayne Bay, a uniquely tropical lagoon harboring crocodiles, manatees, dolphins, and Caribbean fish. Tropical trees cover its islands, while the world's fourth-longest coral reef sits offshore. Native Americans lived here thousands of years ago; the Spanish held it for 200 years. In the late 1800s, hardy homesteaders created an agricultural and fishing community. In the 1920s and 1930s, it became a playground for the newly rich and famous. To protect these unique natural and historical resources and to assure its enjoyment by future generations, a half century ago, the federal government created Biscayne National Monument, which later became Biscayne National Park.