At the border of Brazil and Argentina, we explore the biggest waterfalls in the world – the Iguazu Falls. Over a million tourists visit the 2.7 kilometres wide waterfalls every year but this paradise is now endangered as the rainforest has given way to huge tobacco farms and tea plantations, seriously affecting the Guarani tribe who inhabit the area. Jaguars are also in dramatic decline and we follow specialist rangers in their quest to save the last remaining animals.