Old Town is a genuine open-air museum in the form of a village with a main square, Plaza de Las Armas, and historic wood, adobe or brick houses that are characteristic of southern California between 1821 and 1872, during the American and then Mexican occupations. In 1872, fire laid waste to much of Old Town, thus hastening the displacement of San Diego's business center to New Town. Pop into the Visitor Center and get a detailed map for a journey back in time.