In which state is XXX located?
Buenos Aires
The city of Buenos Aires lies in the pampa region, except for some zones like the Buenos Aires Ecological Reserve, the Boca Juniors (football) Club ``sports city'', Jorge Newbery Airport, the Puerto Madero neighborhood and the main port itself; these were all built on reclaimed land along the coasts of the Rio de la Plata (the world's widest river).