I agree, limited time means local things only... this is my list.
I haven't been to South America in a while (I used to work in Latin America from 1990-2000), some places were starting to get run down and other were starting to see an increase in crime. Don't know how some would be today...
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Chile: I have family here, last time I saw them was in 1997 (My mother is Perúvian)
- Plaza de Armas - A lot of historical buildings in the area.
- San Cristobal - Take the funicular up unless you love exertion
- Lastarria
- Parque Forestal
IF you happen to stop in Punta Areñas, then there is ONE place you need to frequent is the bar of the Los Navegantes Hotel. A lot of scientist who are on their way to Antarctica stay here and the conversations you can strike up are incredible... The other place is the German bar, called Alemán's (Spanish for German).
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Montevideo (1996): Not really much to do ... Depending on your timing, I'd suggest renting a car and taking a trip to Punta del Este to the beaches and then take the ferry back over to Buenos Aires to catch up with your cruise ship... if not, then:
- Old town
- Parque Prado (and the botanial gardens)
- Rambla (maybe... nice, but little else to do)
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Buenos Aires (1996): I have family here as well... My favorite city in the world!
- La Recoleta (don't forget the cemetary where Eva Perón is buried). There is a MASSIVE tree with big wooden supports that keep it from falling down. The best restaurants in the city are here...
- Casa Rosada
- There's a coffee shop close to the corner of "La Florida" and "La Valle"... great for people watching while you have a "cuppa" (Both streets in this area are "walking malls". You'll see a lot of street Tango's here... but................................ ....
- La Boca.... Holy Crap-O-La Batman... this place is great... The most colorful place you will ever see and witness the lively street tangos...
- So much more to see, but I suspect that your cruise will line you up....
- Last time I was there, a new BIG and in HUGE area was being built along the port to cater for new fancy restaurants. Considering the Argentines passion & love of food and wine, I'd assume that this place has gone feral with people...
- Malbec's... don't forget to drink Malbec's.... best in the world, period.