 A series of levees on the park's eastern border marks the line between urban and protected areas, but development into these areas threatens the park system. Florida still attracts nearly a thousand new residents every day, and building residential, commercial and industrial zones near Everglades National Park stresses the water balance and ecosystems within the park. On the park's western border, Fort Myers, Naples and Cape Coral are expanding, but no system of levees exists to mark that border. National Geographic rated both Everglades National Park and Big Cypress National Preserve the lowest-scoring parks in North America, at 32 out of 100. Their scoring system rated 55 parks in terms of sustainable tourism, destination quality, and park management. The experts who compiled the results justified the score by stating: "Encroachment by housing and retail development has thrown the precious ecosystem into a tailspin, and if humankind doesn 't back off, there will be nothing left of one of this country's most amazing treasures".
