Initially, Mexicans established missions and small rancherias (hamlets) in what is now the Southwest; in California, a mission-pueblo-presidio structure ordered religious, civil, and military life for both American Indians as well as the Spanish/Mexican newcomers. In the twentieth century, immigration enlarged some of these locales, but more often new settlements were established near work sites such as ranches, mines, railroad tracks, cash crop fields, and light industries. The railroad network helped create a migrant stream to the Midwest to Chicago and other industrial cities. The word barrio (neighborhood) came to be associated with these settlements in both rural and urban regions. Since the end of World War II, the Latino population has become increasingly urban, a trend that continues today, though pockets of traditional culture still exist, especially in areas such as New Mexico and south Texas. Puerto Ricans have established their own barrios in the eastern and midwestern cities. World War II was a watershed period as it created a demand for more workers and soldiers, and Puerto Rican communities expanded as a result. A unique arrangement facilitating travel between the mainland and island has tended to strengthen Puerto Rican culture and community. Arriving much later than the other Latino groups, Cubans and Central Americans have settled mainly in cities. Cubans, in fact, have achieved major economic and political influence in Miami, Florida. The U.S. government attempted to widely disperse the recent Marielitos wave, but in time even these immigrants gravitated to established Cuban enclaves.