Sediment gathers in the mouth of the Quaraí, forming a green crescent two miles from tip to tip where three nations' borders touch somewhere in the water: no one is sure where. Argentina focuses its disputing energies elsewhere, arguing with others over atolls and ice sheets, but for Uruguay and Brazil it all comes down to the Quaraí. No one can agree where the river ends—at the western or eastern tip of the island. Just as upstream, where the river forks into two branches that carve a landlocked semi-island from hills and woods, both tributaries working hard to ferry that disputed territory westward in bits and sediment pieces, no one can agree which branch represents the true source: just as no one can agree where it ends, no one can agree where it all begins.
