Located principally in southwestern Brazil but with small areas within neighbouring Bolivia and Paraguay too, Pantanal (which is Spanish for ‘marshland’) covers a surface area of 150,000 km² (57,915 miles²) (greater than the total surface area of England! During the rainy season (December-May), 80 per cent of Pantanal is flooded, and it contains the greatest diversity of water plants in the world. As Sudd in Sudan has sometimes been referred to as the world’s largest swamp. However, even in high flood waters its total area only slightly exceeds 30,000 km² (11,585 miles²), and thus falls far short of Pantanal’s area.
Comments below may relate to previous holders of this record.