Argentina: las cataratas de Iguazú
Translated from the French original — read it here.
Argentina, 25 May
The Iguazú Falls are considered unmissable, which worked out well: I had to head back up towards Brazil, so they were on my way — they sit almost exactly on the border between Brazil and Argentina.

So I left Buenos Aires in the early afternoon and set off for 15 hours on a bus :-( . The "cama" class of bus service is among the most comfortable the Argentine transport companies offer, and I admit I feel slightly guilty for taking it every single time — travelling in the most "luxurious" service isn't a great look for the "adventurous backpacker" :-D, but honestly... I don't much care, and besides it isn't excessively more expensive... and it makes up for the hotel night I'm not paying for by travelling overnight.
I got to the town at 8am, dropped my bag at the hostel and rushed off to catch the shuttle to the falls. A quick aside on my hostel: I picked one very close to the bus station, so as not to struggle too much with my bag. The shuttles heading to the falls also go via that station, so it isn't a bad idea to pick a base nearby, especially if you don't have a vehicle.
After the 20-minute shuttle, once I reached the first falls, I witnessed a breathtaking spectacle... Really, it was magnificent, one to file among those moments where nature shows you just how very small you are in front of it. I think the park is very well run: access to the falls is well signposted, with routes for people with reduced mobility. I took photos of course, but the more I look at them the more I realise how far they fall short of the wonders I got to admire.

Visiting the Iguazú Falls, you also get the pleasure of meeting a fair number of "half-wild" animals — they've had time to get used to the presence of tourists and they come very, very close to ask for food... Better not to amuse yourself by feeding one, because there are ten more right behind who'll come running, and at that point it gets downright scary.

So I can confirm that this corner of the world is well worth the detour. I'd also advise not stopping at the falls but taking a walk around the town of Puerto Iguazú as well... I realised a bit late, but it's bigger and more interesting than it looks.