Buenos Aires used to be a great city to visit, with a ton to do, good food, and low prices. It's still most of that, but it's not nearly as cheap since the end of currency controls.
The city is full of interesting architecture and monuments, with the opera house being one of the largest in the world.
It isn't limited to classical architecture either, as there's a large Japanese garden and significant chinatown.
I was very lucky to visit Montevideo during the 2025 Día del Patrimonio Celebrating Uruguay's Heritage. A huge variety of locations were open that would normally be closed to the public, and I was able to visit a number of them including the Palacio Legislativo, French Embassy, Piria Palace, and the Montevideo Naval Base.
As a place to visit, there wasn't a huge amount to do within Montevideo itself. There were museums, but generally small. I did enjoy the tile museum, though! Restaurants were good, but not particularly cheap, and the hours tended to be quite limited (evenings, and maybe 12-3pm).
If Montevideo had limited attractions, Asuncion went a step further. There were still things to do, but I don't think I would have been able to spend more than a weekend on tourist stuff.
Iguazu Falls is a very large system of waterfalls on the border of Argentina and Brazil. It was fun to visit, but taught me that my rain jacket really needs an upgrade and that viewing a waterfall during a thunderstorm does not really add to the experience. Still, there were some breaks in the rain to get some good views, but I'm pretty sure this day gave me a pretty nasty cough.
I saw Devil's Throat first, while things were still dry. Impressive!
This Jay was kind enough to stay still long enough for a clear photo. The Coatis (South American Raccoons) were much more common but far less cooperative in every other way, agressively stealing food.
There really were some spectacular views! Unfortunately this is about when the rain started to pick up, and photos through the rain really didn't turn out well.
Argentina has yet to hear of OSHA, and was perfectly happy to run tour boats during a thunderstorm.
And of course, the view of Argentina (foreground) Brazil (right) and Paraguay (left) at the triple frontier.
