Corumbá

Corumbá needs 2 days: boating through the Pantanal, the world's largest tropical wetland, spotting caimans, capybaras and birds on one day, and optionally a night safari in search of jaguars on the other. July-September, with the lowest water levels, brings the best wildlife viewing. It's mid-to-upper priced due to mandatory guided tours. It's the «capital of the Pantanal» and a border city with Bolivia on the Paraguay river, and the wetland around it is a UNESCO Natural World Heritage Site, with one of the highest concentrations of wildlife in South America.