La Serena

La Serena needs 2 days: touring the colonial center, with over 20 churches and the Faro Monumental lighthouse on the waterfront, on one, and a nighttime excursion to an astronomical observatory on the other. December-March is the best beach season, though the clear sky draws visitors year-round. It's mid-priced, cheaper than San Pedro de Atacama for the same kind of astro-tourism. It's Chile's second-oldest city, founded in 1544, and its proximity to the Elqui Valley made it the usual gateway to the area with the highest concentration of professional astronomical observatories in the southern hemisphere.