Iguazu Falls is possibly the most impressive set of waterfalls in the world, and is only rivaled by Victoria Falls (which is located in Africa). Iguazu Falls is located on the boarders of Argentina, Brazil, and Paraguay. Iguazu Falls is a part of the World Heritage Site. Iguazu Falls features the massive waterfall the Devils Throat (Garganta del Diablo). This huge fall is formed two rivers joining together on the boarder of Brazil and Argentina. Iguazu falls has a series of falls that give you about a 270 degree view of water falls! It also is home to over 2,000 different species of plant life different types of wildlife like: anteaters, monkeys, butterflies, jaguars, and tapirs. This is a must see site when traveling through South America!
You can access the waterfalls from Brazil or Argentina. Both sides offer different views of the falls. Iguazu Falls has an airport that is available for tourist that are trying to travel rapidly through South America. You can get into this airport by flying out of Sao Paolo and Rio De Janeiro, Brazil or from Buenos Aires, Argentina. These are short flights from either country and probably cost around $200-250 US Dollars. The other option is to take the bus. This is the most economical way for a budget traveler. The bus trip from Buenos Aires is a long trip (20 hours). I would suggest making a stop in Rosario (supposed to have the most beautiful people in Argentina) on the way up to the falls from Buenos Aires. If you are traveling to the falls from Rio De Janeiro, Brazil, I would suggest to stop at the beaches of Florianopolis!
If you are trying to access the Falls from the Brazilian side you will more than likely stay in the city of Foz do Iguacu. If you are staying on the Argentina side of the falls you will be staying in the city of Puerto Iguazu. There are hostels available in both cities. I would suggest to book your hostel a day or two in advance before traveling in the during the peak season (summer), because a lot of hostels get booked and it is hard to find places to stay. Most travelers only stay 1-3 days at the Falls. I would suggest to dedicate 1 day on the Argentina side, and the 1/2-1 day on the Brazilian side. I would suggest more time on the Argentina side, because the panoramic views are better on the Argentina side.
Once you pay to get into the Iguazu National Park there are a lot of different paths you can take to see the different views of the falls. There is no wrong way to go! The park employees will give you a map when you enter the park. This map will show you all the walk ways, and different paths that you can follow to different view points. One path leads to the lower part of the falls. You are able to take a boat tour of the falls down this path. You actually go pretty close to the Devil's Throat, and actually get drenched by going almost underneath of a different waterfall.
If you decide to go see the view from the upper trails you can take a train that leads from the entrance of the park to the very end of the park. At the end of the train tracks you will have to walk about 1/2 a mile to reach the Devil's Throat! From there you will able to see great views, and see the power of the famous waterfall!
I have heard multiple funny stories about coaties actually trying to attack humans. These raccoon looking animals have very good smell. They can actually smell when you are carrying fruit in your back pack. I heard a story from another traveler when I was at my hostel that she had bananas in her bag while she was walking down some paths. All of a sudden these animals came out and started following her and would not leave her alone. When she stopped they started jumping for her bag until she dropped it and got the fruit out!
It can get very very hot at the Falls. Sometimes all you want to do is jump in the water, but this is not posible. There is one hidden spot that is off a path in the beginning of the park on the Argetina side. I can't remember exactly how to get there, but I would ask somebody in your hostel before you go to the park for the day! You will be able to hang out in a little lagoon, and swim underneath a waterfall!