The falls are part of a singular practically virgin jungle ecosystem protected by Argentine and Brazilian national parks on either side of the cascades. The vegetation is mostly subtropical wet forest rich in lianas and epiphytes, which around the falls is particularly luxuriant due to the constant spray. The fauna are typical of the region and include tapir, coati, tamandua, and raccoon. The site is particularly rich in bird species with almost half of Argentina's bird species found there.
Threatened mammals such as the jaguar, ocelot and tiger-cat number among the carnivores, and the giant anteater and Brazilian otter are found. There are jungle trails and bird hikes. Plan a full day in the park to fully enjoy the wildlife flora and fauna.
Access to the Falls and the Iguaçu National Park is usually done through one of the three cities in the so-called tri-border between Brazil, Argentina and Paraguay. The city on the Brazilian side is Foz do Iguaçu - big and reasonably safe by Brazilian standards. The town on the Argentine side is called Puerto Iguazu and is small and pretty. The Brazilian Foz do Iguaçu International Airport (IGU) is close to the city and the falls, while the Argentine Cataratas del Iguazú International Airport (IGR) is several kilometers from the Iguassu Falls and from the neighboring city Puerto Iguazu. The Argentinian airport has direct flights from Buenos Aires and several Brazilian airlines as offer service from the main Brazilian cities to Foz do Iguaçu.
If you arrive at Cataratas del Iguazu International Airport, there is a taxi stand at the baggage claim where you can book transfer to either Puerto Iguazu (if you're staying in town) or the Sheraton Hotel if you're staying there. Consider renting a car instead to give you more flexibility, especially if you plan to spend a day in Brazil as well. It's about 15 minutes’ drive from the airport to the park/Sheraton and about 30-45 minutes to Puerto Iguazu.
Other than visiting the Falls and the National Park and having a drink/dinner at either Puerto Iguazu or Foz de Iguazo there isn't much else to do in this area. So don't plan on staying your entire holiday here, 2 or max 3 days should do it. For the Brazil side you need no more than 4 hours total.