The Everglades of Florida begin near Orlando with the Kissimmee River, which discharges into the vast but shallow Lake Okeechobee. Water leaving the lake in the wet season forms a slow-moving river flowing southward across a limestone shelf to Florida Bay at the southern end of the state. The primary feature of the Everglades is the sawgrass marsh. Sloughs, or free-flowing channels of water, develop in between sawgrass prairies. Wet prairies are slightly elevated like sawgrass marshes, but with greater plant diversity. Everglades National Park protects an unparalleled landscape that provides important habitat for numerous rare and endangered species like the manatee, American crocodile, and the elusive Florida panther. The Everglades are a World Heritage Site, International Biosphere Reserve, a Wetland of International Importance, and a specially protected areas under the Cartagena Treaty.