The Beagle conflict was a border dispute between Chile and Argentina over the possession of Picton, Lennox and Nueva islands and the scope of the maritime jurisdiction associated with those islands that brought the countries to the brink of war in 1978.

The islands are strategically located off the south edge of Tierra del Fuego and at the east end of the Beagle Channel. The Beagle Channel, the Straits of Magellan and the Drake Passage are the only three waterways between the Pacific Ocean and the Atlantic Ocean in the southern hemisphere.

After refusing to abide by a binding international award giving the islands to Chile, the Argentine junta advanced the nation to war in 1978 in order to produce a boundary consistent with Argentine claims.

The conflict was resolved through papal mediation and since 1984 Argentina recognizes the islands as Chilean territory. The 1984 treaty also resolves several collateral issues of great importance, including navigation rights, sovereignty over other islands in the Fuegian Archipelago, delimitation of the Straits of Magellan, and maritime boundaries south to Cape Horn and beyond.

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