PLANET EARTH Freshwater
Successful displays lead to mating. Even for giant rivers like the Amazon the journey to the sea is not always smooth or uninterrupted. Iguassu Falls（伊瓜苏瀑布） on the border of Brazil and Argentina（阿根廷） is one of the widest waterfalls in the world - one and a half miles across. In flood 30 million liters of water spill over every second.
All the world's great broad waterfalls: Victoria, Niagara（尼亚加拉） and here, Iguassu, are only found in the** lower courses**（低河道） of their rivers. In their final stages rivers broaden and flow wearily across their flat flood plains. Each wet season here, in Brazil, the Parana（巴拉那） river overflows its banks and floods an area the size of England.
The Pantanal（大沼泽，地名） - the world's largest wetland（湿地）. In these slow-flowing waters aquatic plants（水生植物） flourish like the Victoria giant water lily with leaves two meters across. These underwater forests are nursery grounds for fish. Over 300 species breed here, including red-bellied piranha（红腹锯脂鲤，小淡水鱼的一种，通俗意义上的食人鱼的一类） and other predators, like the spectacle caiman（眼镜凯门鳄）. Ripening fig trees（无花果树） overhanging the water's edge provide welcome food for shoals of hungry fish.
