Before Buenos Aires I was spending four days at Iguazu. Two days at Brazil side and two days at Argentinian side. If planning to visit Iguazu falls in the future I have a tip for you. Stay at Puerto Iguazu, Argentina and just visit Brazil side. Don't stay at Foz de Iguazu, Brazil. It's more 1) cheap, 2) safe and 3) nicer to stay at small village of Puerto Iguazu than in a bigger city of Foz de Iguazu. You can visit Brazil side falls and Itaipu dam in one day. Don't go to Paraguay side, the crossing of the border takes two hours and it's crowded with lot's of cars and people. Itaipu dam can be visited from Brazil side as well.
On the border of three countries. Paraguay on the left, Brazil on the right and Argentina on front. River Parana flows between Paraguay and Brazil and river Iguazu between Brazil and Argentina. This is the point where Iguazu river joins Parana river.
Falls were amazing and giant, but once you have seen them you have seen them. That's it. Now I have visited all the major tourist attractions during this trip, Galapagos islands, Machu Picchu, Chichen Itza, Tikal, Titicaca, Iguazu falls, Salt flats. The rest of the trip doesn't provide any more tourist attractions, thanks god! I'll skip Rio de Janeiro and it's beaches (I have seen and will see so many beaches and even better ones).
Part of the Iguazu falls
In order to complete this water subject I'll add still a photo of the pool, which was actively used at hotel. Temperature is constantly above +30 degrees :)
Pool at hotel