"Petra es un municipio de la comunidad autónoma de Islas Baleares, España. Situado en la isla de Mallorca, en la comarca de la Pla de Mallorca."
"Petra is a town and municipality on the Mediterranean island of Majorca, in the Spanish autonomous community of the Balearic Islands. "Petra" means "rock" in Latin. Petra is the birthplace of St. Junípero Serra (1713-1784), a Franciscan friar who founded the first nine of 21 Spanish missions in California from San Diego to San Francisco."