Argentina - North
Iguazu Falls National Park - Tucked into a corner that is shared by Argentina, Brazil, and Paraguay this is one of the great physical wonders of the world, and one of the four "must sees" of Argentina. The waterfall is spectacular beyond expectation: Go to Garganta del Diablo (Devil's Throat) where you'll experience the magic rainbows. The Park has about four hundred bird species such as parrots, colibries, and toucans as well as over two thousand plant species including gigantic trees and brilliant orchids not to mention the jaguars and caimans.
Iguazu Falls (Foz do Iguacu) - Tucked into a corner shared by Argentina, Brazil and Paraguay, Iguazu Falls National Park is one of the great natural wonders of the world. Iguazu Falls are in both Argentina and Brazil, and there are activities on each side. The park also has hundreds of bird species, colorful parrots and toucans, gigantic trees and brilliant orchids. Plan on taking two days to visit - there are some great things for kids.
On the Brazil side, take a boat ride into the falls! It's a short ride on a large hard-bottomed raft that literally goes into the water, and you will get soaked. This is perfect for kids over the age of 8, or really adventurous younger ones. Purchase tickets from the kiosks located inside the park.
Within the park are many different walks and overlooks to view the falls from above. On the Brazilian side, go to Devil's Throat overlook (Garganta del Diablo) to experience rainbows and the best views. On the Argentina side, there are more walking paths and bridges, the Circuito Superior and Circuito Inferior, so do both.
For younger kids who may want to walk less, hop on the train, Tren de la Selva.
Tip: Arrive at the park before 9am, or after 11am. (In between those hours, all the tour buses show up and it can get really crowded.)
Explore the Jesuit ghost missions - Almost swallowed by the jungles near Posadas you'll find the old Jesuit missions: a twist on the ghost towns of the old west. Check out San Ignacio Mini, Candelaria, Loreto, Santa Ana and Santa Maria.
Hit the water - Throughout the region there are rafting and canoeing excursions - as well as beautiful waterfalls and lovely pools for swimming.
Take a thermal bath - Presidencia Roque Sáenz Peña is famous for its thermal baths that will relax you after a hectic day of hiking!
Head into the Ibera Marshes - 700.000 hectares of swamp land and lagoons filled with monkeys, swamp deer, turtles, caimans and home to the largest rodent in the world: the capybaras.
Fun food
"Terere" is a drink made from the mate herb native to this region - try it cold and mixed with aromatic herbs. Before you dig into that great looking grilled steak in this region you should ask - it's likely to be ox! Expect a slightly heavier flavor.
Shopping
In Resistencia's Toba district and Posadas' Paraguayo Par you'll find a lot to choose from: native masks and carvings in palo santo. Or hunt for a really beautiful agates, amethyst, geodes to take home.