The cities of Foz do Iguaçu and Puerto Iguazú, form together with Ciudad del Este, the triple border between Brazil, Argentina and Paraguay. Ciudad del Este is the largest among the three, with a population of about 300,000 inhabitants. Located 330km (205mi) east of the Paraguayan capital, Asunción, the main attraction of this city is its role as a giant shopping mall where imported products like electronics, cosmetics, beverages and clothing can be found at competitive prices (and quality often dubious). Anyways, this is a pretty ugly, dirty and some would also say unsafe city, being better avoided.
Across the Paraná River, lies the Brazilian city of Foz do Iguaçu. With 260,000 inhabitants, this is a convenient base for exploring the region. Foz do Iguaçu also houses the main airport in the region with flights to several Brazilian cities as well as international destinations such as Santiago, in Chile. Puerto Iguazú, in Argentina, is the smallest of the three, but also offers convenient options of accommodation and an airport that connects it mainly with Buenos Aires, but also with some other cities.
The main attraction of the region, and the reason why almost all leisure tourists come here is pretty obvious. The Iguazu Falls, located on the border between Brazil and Argentina are one of the greatest natural spectacles of the planet. With an average flow greater than 1,700 cubic meters of water per second, this is a view that will be surely rooted in your memory and that should be enjoyed with the deserved calm. To experience the best that the falls have to offer, plan to stay at least a day on each side of the border.
Since most of the waterfalls are in Argentine territory, this side of the border allows for a closer view of the falls. The great system of trails and walkways found on this side allows you to observe the falls from different angles, getting quite close to the Devil's Throat, the main waterfall of the park. The Brazilian side is an excellent addition to this experience, allowing great photo opportunities as it takes a more panoramic view of the falls system. Both sides of the falls are part of national parks in Brazil and Argentina, for which there are entrance fees. You can move between Puerto Iguazú and Foz do Iguaçu and between each city and its respective side of the falls in public transport.
Besides the falls, visitors to the Brazilian side can take the opportunity to see what until recently was the largest hydroelectric power plant in the world. The Itaipu Dam, located on the Paraná River, belongs equally to Brazil and Paraguay and provides about 17% of the energy consumed in Brazil and 75% of the electricity used in Paraguay.
On the Argentine side, a great option to go beyond the falls is to get to know some of the Jesuit Reductions located in the south of the Misiones province. The provincial capital, Posadas, is located 300km (185mi) south of Puerto Iguazú and is a great base to explore the ruins of Santa Ana, Loreto and especially San Ignacio Miní. To visit the best preserved ruins in the area, however, it is necessary to cross the border between Posadas and Encarnación, Paraguay, and follow another 30km (19mi) in Paraguayan territory until you get to Trinidad.
Those enthusiastic about the history of the Jesuit Reductions can also return to Brazil to visit the remains of the ancient Eastern Missions, or Seven Peoples of the Missions, in the state of Rio Grande do Sul. Its greatest symbol, São Miguel das Missões, is 250km (155mi) away from Posadas. Otherwise, Buenos Aires is 1,000km (620mi) south of Posadas. On the Brazilian side, Curitiba is 635km (395mi) away from Foz do Iguaçu, Florianópolis is 935km (580mi) and São Paulo is 1,050km (650mi) away from the triple border.