Spending three whole weeks in Argentina really opens the doors, either to see some of the prime destinations in a more thorough and leisurely way, or to add destinations and sights where logistics are more complex. Near Buenos Aires, for instance, it’s easier to add worthwhile second-tier destinations like the Paraná Delta, the gaucho capital of San Antonio de Areco, the river port of Rosario, the Sierras of Buenos Aires Province, or the South Atlantic beaches in and around Mar del Plata. It’s even possible to hop across the River Plate to the World Heritage Site of Colonia, Uruguay.

One of the best areas to spend extra time, though, would be the northwest, where you’ll find truly off-the-beaten-track sights like the Jujuy provincial village of Iruya, the cloud forest national parks of the yungas, and the stunning desert highlands in and around Cachi. Cities such as Córdoba and Tucumán, with their colonial heritage and scenic nearby Sierras, are other possible extensions.

While Cuyo is Argentina’s wine cask, its backcountry can boast some of the world’s highest mountains, topped by 6,959-meter Cerro Aconcagua. A month’s not long enough to climb Aconcagua while seeing or doing anything else—acclimatizing to the altitude takes at least a week—but it would be possible to trek to base camp and back. That sort of time could also be used to visit paleontological parks like San Luis Province’s Parque Nacional Las Quijadas, San Juan’s Parque Provincial Ischigualasto, and nearby La Rioja’s Parque Nacional Talampaya.

It’s Patagonia, though, where the extra time can help conquer distance and rough roads to permit extended hiking in the northern lake district or the Fitz Roy Sector of Los Glaciares, excursions to dinosaur sites in Neuquén Province, archaeological sites like the Cueva de las Manos, and side trips like Chile’s magnificent Parque Nacional Torres del Paine.

Day 1
Arrive at Aeropuerto Internacional Ministro Pistarini (Ezeiza) and transfer to a Buenos Aires hotel, with the afternoon free for sightseeing.

Day 2
Early morning flight to Puerto Iguazú, with the afternoon at the falls; if the timing’s right, take the full-moon tour.

Day 3
Excursion to the Brazilian side of the falls; alternatively, hike the rainforest on the Argentine side or visit the historic Jesuit mission at San Ignacio.

Day 4
Overland by bus to Posadas, capital of Misiones Province, and by hired jeep with driver to Colonia Carlos Pellegrini, in the Esteros del Iberá wetlands.

Day 5
Full-day excursion among the floating islands of the Iberá marshes to see their wealth of subtropical wildlife.

Day 6
Overland transfer to the provincial capital of Corrientes, then fly to El Calafate via Buenos Aires, taking most of the day. Time permitting, visit a working estancia near El Calafate for an asado.

Day 7
Full-day excursion to the Moreno Glacier, Parque Nacional Los Glaciares.

Day 8
Overland by bus or rental car to the Fitz Roy Sector of Parque Nacional Los Glaciares, with accommodations at the settlement of El Chaltén. Depending on arrival time, you might squeeze in a swift hike to view Cerro Torre’s glaciated needle.

Day 9
Strenuous full-day hike to Laguna de los Tres, with stupendous views of Cerro Fitz Roy. Evening return to El Calafate.

Day 10
Morning flight to Ushuaia, capital of Tierra del Fuego, followed by a wildlife-viewing excursion on the legendary Beagle Channel.

Day 11
Full-day excursion to Parque Nacional Tierra del Fuego, with options for multiple short hikes. Be sure not to miss Museo Marítimo de Ushuaia, Ushuaia’s misleadingly named prison museum.

Day 12
Morning flight to Trelew and transfer to Puerto Madryn, with an afternoon visit to the city’s Ecocentro environmental museum. You should still have time for sunning on the beach or more active pursuits like diving or windsurfing.

Day 13
Full-day excursion by tour bus or rental car to Península Valdés where, depending on the season, there’ll be penguins, orcas, or right whales. Many other species—rheas, guanacos, and sea lions, for instance—are present all year.

Day 14
Full-day excursion to the gigantic Magellanic penguin colony at Punta Tombo, south of Trelew. On the way back, visit Trelew’s state-of-the-art paleontology museum and take Welsh tea at Gaiman.

Day 15
Return flight to Buenos Aires and on to the city of Salta, with the afternoon free to view its colonial monuments.

Day 16
Full day tour of the altiplano high steppe; in the winter dry season, take the “Train to the Clouds.”

Day 17
Excursion to archaeological sites and colonial monuments of the Quebrada de Humahuaca, a World Heritage Site in Jujuy Province. Spend the night in Purmamarca or Tilcara.

Day 18
Morning tour to Iruya, a remote and stunningly scenic Andean village, with an afternoon return to Salta.

Day 19
Return flight to Buenos Aires, with the afternoon and evening free for sightseeing and perhaps a tango floor show.

Day 20
Overland excursion to the gaucho capital of San Antonio de Areco or ferry across the River Plate to the World Heritage Site of Colonia, Uruguay.

Day 21
Full day for exploring Buenos Aires before an evening departure.