On our visit to Iguazu on a land trip of Chile and Argentina about ten years ago, we spent three days/two nights at Igauzu. One can, however, see the key sites in less time than that, with some planning. We spent the first afternoon walking the trails along the falls on the Argentine side (we were staying at the International - I think that is now the Sheraton). The next day, we walked the trails on the Brazilian side, took the helicopter over the falls, and then took the zodiac trip right to the base of the falls (fabulous, except for the fact that either the water or the wild zodiac ride killed my camera - a small sacrifice for a memory of a lifetime). Thus, we saw the magnificent falls from both sides on land, from the air, and from the river below. On the Argentine side, you certainly don't need a guide, since the trails are well marked. And now with the visa issues, I don't know how easy it is to get over to the Brazilian side for the zodiac trip or the helicopter ride. In summary, you can do it in a one-night trip, although not as well as in a two-night stay. You can manage without a guide, unless that makes it easier to get to the Brazilian side. It is, as Marcie noted, very, very, very HOT. Thank heaven for the great AC in the hotel. And having a pisco sour on the balcony of your room in that hotel while looking out over the falls and remembering the scenes from "The Mission" (which were filmed on that Argentine side of the falls) is a memory of truly remarkable proportions. If you haven't been, you simply must go. BA is fun (as long as you can tolerate the aroma of grilled meat); but Iguazu is magical. Cheers, Fred