Forest hammock of slash pine and saw palmetto, Everglades National Park, Florida, United States (© Mary Liz Austin/Alamy)

What happens when water moves too slowly to notice? In Everglades National Park, it shapes everything. Covering more than 2,300 square miles, the park was established in 1947 to protect a wetland system unlike any other in the United States. As a recognised UNESCO World Heritage Site, the park's elevated pinelands rise above the marshes and prairies that form one of the world's largest wetland systems.