Canoe paddling in Okefenokee National Wildlife Refuge, Georgia

Serene waters on a 'trembling earth'. Okefenokee National Wildlife Refuge, Florida, USA

Wetlands are biologically diverse systems that sequester carbon, increase water quality, and provide sanctuary to at least one third of all endangered and threatened species. And yet, wetlands themselves are threatened. More than half of the 221 million acres of wetlands in 48 contiguous US states have been destroyed.

Georgia's Okefenokee Swamp, seen here, is a thriving wetland and the largest blackwater ecosystem remaining in North America. Here you'll find dozens of bird species, as well as lots of amphibians, reptiles and other critters. The Okefenokee Swamp gets its name from a Native American word meaning 'trembling earth'.