And another fun fact... the Falls used to belong to Paraguay.
Thanks to the War of the Triple alliance in which Diego Costa, Suarez, and Angel DiveMaria invaded Paraguay (albeit in response to Paraguay sending troops through Argentina without permission to help a Uruguayan populist political movement that the Brazilian backed gov't sought to crush), Paraguay lost a full 33% of it's territory, including said Falls. The Brazilian's maintained their control of Uruguay as a pawn state and all three ganged up on overwhelmed and overmatched Paraguay.
The Argentines and Uruguayans left halfway through when it was clear Paraguay was defeated and Lopez, the General, was on the run. Brazil, however, kept pressing and chasing all through the country.
When the dust settled, Paraguay lost a chunk of land about the size of Ingerland and Scotland, including the Falls. (And the tourist dollars they bring.)
Further, Paraguay lost an estimated 90% of it's male population. Yep. 90%.
Ninety percent. Women and emaciated boys in rags with sharpened sticks were the last defenders of the country. The country didn't hit near a 50:50 ratio until like 2000, so if you had a time machine, were looking to "score", and didn't mind dealing with heat and all sorts of tropical diseases, Paraguay in the later half of the 19th century would be your destination.
Brazil and Argentina held huge tracts of land. One Argentine $$$$ family held a massive ranch that was so big it had it's own general store and shopping for ranch hands. Was like a week and change ride to the nearest other place.
The Uruguayans were remorseful after the fact and returned all the loot they stole, so one of the nicer parks downtown was named the Plaza Uruguay as a thanks.
Paraguay also celebrate a Children's Day - not as a celebration of children in general, but as a reminder of those who died defending the country - as well as a Women's Day, honoring those who fought and held the country together afterwards.

(And back I go to work. Thanks for the diversion.)