Today’s a national holiday, the celebration of 25 May 1810 in which the Spanish viceroyal Cisneros was disposed by the first Junta that would govern the land later known as Argentina. The new local government assumed its power in the Cabildo, a colonial building that still stands on the city’s main square. Opposite the Cabildo is the Casa Rosada, the seat of the Presidential government. The plaza is now known as Plaza de Mayo.