Iguazu Falls, Argentina
I only spent a day and a half here (and wouldn't recommend spending much longer, because outside of the park there is literally nothing to see or do), but wow!!! What an amazing place. Iguazu Falls is right at the corner of the Argentina/Brazil/Paraguay border, and the falls themselves are accessible from either Brazil or Argentina. If you have the time and money to spare, I hear that the view from the Brazilian side is almost as good, but you may need to plan ahead a bit to get a Brazilian visa. You can fly here directly (there's an international airport) or take one of the long distance buses as I did, about 18 hours from Buenos Aires. It wasn't terrible, with fully reclining seats about like a first class airplane seat but a lot harder to sleep in due to bumpiness and winding roads. It wasn't a trip I wanted to do twice, so we found a direct flight out of here to Mendoza. Ok, enough talk. Check out these amazing waterfalls! ...