Calhoun Street San Diego by RD Riccoboni. Historic buildings line the street where California and the western United States began. The large house in the background is Casa De Bandini, one of the oldest houses in California is now the Cosmopolitan Hotel and Restaurant. La Casa de Bandini was completed in 1829 and soon became the social center of Old Town. Juan Bandini held various offices during the Mexican regime. When Americans took over, he supplied them with horses and supplies from his rancho.