Argentina and Chile both pulled away from their colonial overlord, Spain, declaring their independence in 1816 and 1818, respectively. You'd think that people in these two nations would want to get along—new nations often struggle with creating the constitutions and governmental organizations that will enable them to succeed—but in this case, the relationship between these two South American countries went sour right away.
And, of course, it was all about whose-owns-this-bit-of-land?
Chile was content, at first, to establish its eastern boundary at the Andes, but then someone started arguing that Chile deserves to own all of Patagonia, which is the entire region at the southern end of South America. (The island Tierra del Fuego is usually included in this region.)
Well, sure, you could make a case that Pedro de Valdivia got the rights to all of Patagonia from the Spanish crown, back in the 16th Century, but you could also point out that Argentina had supported Welsh immigrants in parts of Patagonia. You could argue that Chile just cared about the Straits of Magellan (a bit of sea between mainland South America and the island Tierra del Fuego, through which ships can travel between the Atlantic and Pacific Oceans) and that the Chilean government had seen Patagonia as a useless wasteland. But you could also say, “Hey, Argentina, you already have so much land, and poor little Chile is soooo skinny! Can't you give Chile some more land?”
At any rate, Argentina and Chile squabbled over the land and then signed this treaty, which split Tierra del Fuego and the rest of the disputed lands between the two nations, and which stated that the Straits of Magellan shall be “neutralized for ever, and free navigation assured to the flags of all nations.” In other words, NOBODY is allowed to build military bases there!
A treaty is generally a good thing, a sort of win-win. In this case, however, there still have been disputes over Patagonia. In 2010, for example, the two countries argued over the Southern Icefields, which contain the second largest reserve of potable water in the world!
For more info about Patagonia, check out this earlier post.
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