Iguazu waterfall is the biggest waterfall in the world. It borders Argentina, Brazil and Paraguay, with the Foz do Iguazu on the Brazilian side of the falls. The waterfall can be found in the national park of the same name. The closest you can get to the Devil's Throat can be found on the Brazilian side of the border, though some say the Devil's throat can best be seen over the border in Argentina. It's probably best to visit both sides of the border to make sure you see all of this incredible waterfall.