Premise: Club Atlético Unión de Mar del Plata is an Argentine sports club from Mar del Plata, Buenos Aires Province. The club was founded on December 1, 1926, and its main sports are football and basketball. In football, Unión currently plays in the Torneo Argentino A, which is the regionalised third division of the Argentine football league system.
Hypothesis: The club was first formed on the first of the last month of the year, 1926.