The first must see place on my list for South America was Iguazu falls www.iguazuargentina.com on the Argentina/brazil border. I'd seen photos but the reallity is just breathtaking. Over 2 days on the Argentina side and one on the Brazillian I think I took over 200 photographs, movie clips and sound recordings (thanks for the spare battery tip Roy!). Afer that I ventured up to the Itaipu Dam on the Brazil/Paraguay border. It's the worlds biggest Hydroelectric Dam was almost as impressive as the falls, the spillway can handle 40 times the flow of the Iguazu falls (it's on a bigger river) and as it had been raining heavily recently was on about half flow.