On the border between Argentina and Brazil, the Iguazú Falls — the largest series of waterfalls in the world — are one of South America’s leading attractions. Victoria Falls, in southern Africa, has the world’s largest single curtain of water, but the Iguazú system is both more extensive and easier to see. On the Argentine side, there are approximately 4 miles of metal walkways with dozens of viewpoints. The Upper Circuit and the Lower Circuit paths each take about 90 minutes to complete at a leisurely pace. On the Upper Circuit, there are places where you can stand a few feet from where the river slides into the abyss, while on the Lower Circuit, it is possible to almost reach out and touch the thunderous Bosetti cascade.