The Pantanal is the world´s greatest alluvial floodplain.  It covers an expanse difficult for the imagination to grasp.  Estimates of its size vary, depending on the criteria used to define it.  However, using as an estimate for the entire Pantanal 170,000 km2 (17 million hectares or 42 million acres) — and this is probably low — it would still encompass an area more extensive than many countries, including England, Austria, Hungary, Greece or Ireland. It is larger than 29 of the states in the United States, surpassing New York State, Wisconsin and Florida and an estimated 17 times the size of the remaining Florida Everglades. While the word “pantanal” means “swamp” in Portuguese, it is not a swamp, but rather a landlocked delta of immense  proportion. 
Delimited by the Brazilian high plains to the east, the Chapadas Matogrosseses to the north, and Bolivian highlands to the west.  In rainy years the rio Paraguai swells up to 20 kilometers in width temporarily recreating the "Sea of the Xaraiés" that existed in a time of greater rainfall in the geological past.
What makes the Pantanal all the more unique is its multitude of ecosystems: Influenced by the Savannah lowlands, the Caatinga, the Amazon and Mid Atlantic rainforests, with its extraordinarily concentrated and diverse flora and fauna, we can divide the pantanal into 11 different micro-regions: The Pantanal of Aquidauana, Pantanal of Nhecolândia, Pantanal of Miranda, Pantanal of the Abobral, Pantanal of the Nabileque, Porto Murtinho, Cáceres, Poconé, Barão de  Melgaço, Paraguai, and Paiaguás...The Pantanal of South America is one of the most immense, pristine and biologically rich environments on the planet accounting for over 3% of its wetlands