A U.S. agency said Friday it will nominate the vast, federally protected wildlife refuge in the Okefenokee Swamp for listing as a UNESCO World Heritage site. The National Park Service filed a notice in Washington that it will seek the designation for the Okefenokee National Wildlife Refuge, which sprawls across more than 400,000 acres (161,875 hectares) in southeast Georgia near the Florida state line. Conservation groups say the rare distinction would boost the Okefenokee's profile as one of the world's last intact blackwater swamps and home to abundant alligators, endangered red cockaded woodpeckers, stilt-legged wood storks and more than 400 other animal species.