High Quality Content by WIKIPEDIA articles! The Pantanal is a tropical wetland and the world's largest wetland of any kind. It lies mostly within the Brazilian state of Mato Grosso do Sul but extends into Mato Grosso as well as into portions of Bolivia and Paraguay, sprawling over an area estimated at between 140,000 square kilometers (54,000 sq mi) and 195,000 square kilometers (75,000 sq mi). Various sub-regional ecosystems exist, each with distinct hydrological, geological and ecological characteristics; up to twelve of them have been defined (RADAMBRASIL 1982).