Shirley Manson may only be happy when it rains, but let me tell you, you're camera isn't. I learnt the hard way. The day I arrived at Iguazu Falls it was pissing down like crazy, but I went to see the falls anyway, whipping out my camera at all the incredible vistas that greet you around every bend. BIG mistake. My camera couldn't cope with the humidity and the photos were lost. My advice is, if you arrive at Iguazu on a wet day (and there are plenty of those - where do you think all that water comes from?), yes, still go and see the falls. But leave your camera wrapped in plastic in your daypack and go back the next day (the ticket is half price on the second day) when hopefully the sun is shining, and so will your camera! Happy snapping!