The point of origin of the city is the "Plaza 25 de Mayo" ("25 May Square"), now surrounded by the Municipality ("Palacio de los Leones"), the Basilica Cathedral of Our Lady of the Rosary, the Central Post Office building, the Decorative Art Museum and the emblematic building called "La Bola de Nieve" ("The Snowball"). The streets follow a remarkably regular pattern called "damero" (a checkerboard grid), except in the zone around the Bajada Sargento Cabral, where the streets are somewhat more irregular due to terrain features.