To commemorate the 2010 bicentennial of its salt mines, a polluted tributary of this river was dyed Uriburu Green. It’s not Tampa, but a city along this river created the longest continuous sidewalk in the world inspired by Barcelona’s Rambla. A dialect named for this river is used by the poet Oscar Conde and includes terms named after “Lombard villainy.” This river’s estuary is bounded by a line that runs from Cabo San Antonio to Punta del Este. The Admiral Graf Spee was scuttled in this river after the first naval battle of World War II. The most spoken dialect to use “vos” in place of “tú” originated along this river in neighborhoods like Palermo. The Superclásico is played between a team named for this body of water and Boca Juniors. For 10 points, the tango developed in dancehalls along what river whose estuary borders Montevideo and Buenos Aires? ■END■
ANSWER: Río de la Plata [or Plate River; accept Rioplatense Spanish]
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= Average correct buzz position