Puerto Iguazú is a small Argentine town whose entire reason for being is proximity to one of the world's great natural spectacles: Iguazú Falls. Sitting at the confluence of the Iguazú and Paraná rivers, where Argentina, Brazil, and Paraguay meet, the town is a quiet, low-key base for exploring the national park. Most visitors arrive, spend a day or two at the falls, and leave — but the town itself is pleasant enough and accommodation is plentiful.
The falls are shared between Argentina and Brazil, and most visitors cross to see both sides. The Argentine side (Parque Nacional Iguazú) gets you closer — you walk along elevated walkways right over the cascades and can take a boat into the spray. The highlight is the Garganta del Diablo (Devil's Throat), a U-shaped chasm where the river drops 82 metres in a roaring curtain of white water. The Brazilian side offers the classic panoramic view.
The national park contains a large area of Atlantic rainforest. Coatis — raccoon-like animals with long striped tails — wander the walkways in groups and will steal your lunch if you give them the chance. Toucans and monkeys are common, and the birdlife throughout the park is exceptional.