I ended up missing the bus from Rio to Foz Iguazu, and spent an extra day in Rio. There´s a long story behind it, but I spent some time the next day in a mental health institute in Rio. It was a bizarre experience (I didn´t go for treatment), but the last week had been quite crazy, so being surrounded by lunatics was quite fitting.
The bus to Iguazu took about 24 hours, and after 3 months of travelling in South America, it felt normal. The roads are well paved, the buses have a lot of leg room, and I enjoyed the scenery. Met a couple of other backpackers on the bus and shared a taxi with them to a hostel. The hostel was cheap, but resembled a resort and was almost completely empty. It´s low season right now in this part of Brazil (and Argentina), so I spent the rest of the day lazing around in the hostel. The hostel had a mini-van which took people to the waterfalls, and I signed up for it. The better of the falls are on the Argentinian side, and I realised that I was on a single entry visa. My Brazil visa was going to expire in another 2 days, so I decided to enter Argentina through the national park.
It turned out be very painless. The van driver took care of all the passport stamps for the group, so I entered Argentina without encountering a single immigration official. Spent the rest of the day at the national park around the waterfalls. The falls separate Brazil, Argentina and Paraguay and are very, very impressive. There are quite a few trails (completely paved), and since it´s low season, things were very quiet. Took a lot of pictures, but they didn´t do justice to the falls due to the scale. It was quite mesmerising to watch the volume of water falling, and the vapours rising.
Will upload pictures once I reach Mendoza. Am near the bus terminal right now, waiting for the bus. It´s going to the longest bus ride I´ve done - 36 hours. But from what I´ve heard, buses in Argentina are very comfortable and almost luxurious. More once I reach Mendoza.