01/07/10Iguazu is an exception in my list of wild places: here, the breath-taking scenery more than surpasses the wildlife.
Go to the Garganta del Diablo (from above, in the Argentinean side, or from below, in the Brazilian side) and spend one hour just watching the waters fall, and feeling the clouds of spray shower you. You will emerge completely lost for words.
Summer (December to March) is too crowded, too hot, and there is so much water that it is hard to see the falls, due to the water mist. Much better to go in winter (July).