Mark Brownlow / Low aerial view of Iguazu falls, world's largest waterfalls that straddle Brazil and Argentina, Iguacu Falls NP, South America. BBC Planet Earth series. November 2005

Thomas Mangelsen / Cascades of Iguacu Falls surrounded by tropical rainforest, Iguacu Falls National Park, Brazil

Michael & Patricia Fogden / Iguacu falls as seen from the Brazilian side, Brazil and Argentina border

Konrad Wothe / Rainbow at Iguacu Falls, largest waterfalls in the world, Iguacu National Park, Brazil

Claus Meyer / Aerial view of the Iguacu Falls, Brazil

Norbert Wu / Iguacu Falls, world's largest waterfalls, Brazil and Argentina border

Pete Oxford / Iguazu falls from Brazil, Brazil - Argentina border

Luke Massey / Great dusky swifts (Cypseloides senex) roosting behind one of the falls at Iguassu Falls, Brazil

Luke Massey / Great dusky swifts (Cypseloides senex) roosting behind one of the falls at Iguassu Falls, Brazil

Shane P. White / Double rainbow in mist of waterfall, Devil's Throat, Iguacu Falls, Brazil

Shane P. White / Brown Capuchin (Cebus apella), Iguacu Falls, Argentina

Shane P. White / Rainbow over waterfalls, Bosetti Waterfall, Iguacu Falls, Argentina