The name Pantanal suggests a swamp area (Pantanal stems from "pântano" = swamp) yet this is a low lying plain which floods annually. The greater part of this ecological paradise belongs to Brazil, with a surface area of about 140,000 km2. The Paraguai River traverses the plain from north to south and is the only outflow of the entire area. Precipitation in the region amounts to 800 mm annually. The Paraguai River and its tributaries overflow their banks each year, causing flooding over widespread areas of the plain. Through the sediments of the floods, the earth is made fruitful.