Precious Watersheds - the world's last wetlands

Wetlands are ecosystems that are either permanently or seasonally saturated with water. Wetlands have unique vegetation and soil and may be freshwater, saltwater or brackish and include swamps, marshes and bogs. Wetlands occur naturally on all continents except Antarctica. Wetlands play a vital role in retaining soil nutrients and purifying water. The Convention on Wetlands (Ramsar, Iran, 1972) -- called the "Ramsar Convention" -- is an intergovernmental treaty that embodies the commitments of its member countries to maintain the ecological character of their Wetlands of International Importance and to plan for the "wise use", or sustainable use, of all of the wetlands in their territories. Take a visual tour of some important Ramsar sites of the world.