Oficinas saliteras (nitrate works) were company towns developed to extract and process nitrates in the Antofagasta region of Chile's Atacama desert, one of the world's harshest environments. The two last of these oficinas were María Elena (founded in 1925) and Pedro de Valdivia (1931), whose development marked the introduction of the Guggenheim industrial system. Their urban design was closely related to the industrial cities of Europe and the United States, as well as the Spanish urban tradition. María Elena used an octagonal street plan, while Pedro de Valdivia is based on a crossing pattern.