Tijuana along with its U.S. neighbor San Diego form the largest metropolitan area on the U.S.-Mexican Border with a population of 4.5 million.Economically, a growing middle class whose disposable income has fueled Tijuana's transformation into a modern city with a vibrant culture, a characteristic that has attracted many national and international businesses which had largely shunned the city before. Aside from the middle class, in Tijuana you can reasonably expect to find areas filled with richer people. Tijuana is a transit point for illegal immigration into the United States, as well as a common destination for any illegal Mexican immigrants deported from the west coast of the United States. As such, some areas are swollen with poor people with no roots in the city, who inhabit shantytowns. Apart from these poor migrants, Tijuana is one of the wealthiest cities in Mexico. Some (mainly residential) areas of the city reflect the significant number of wealthy people who inhabit the city.Tijuana's growing reputation as a cosmopolitan city is justified. Not only is the city home to many people who have migrated from within the same country, as well as some native Mexican Indians, but it boasts an important amount of Asian residents, as well as Americans (mostly from neighboring San Diego who have been drawn to Tijuana by cheaper housing), and South Americans from Argentina and Uruguay, among others.Frequent English-speaking visitors to Tijuana use the term "gringo-friendly" for a shop, bar, or restaurant in which a non-Spanish speaking customer will be at ease. A place is gringo-friendly if the staff here is accustomed to dealing with American tourists, if they speak English and have English-language menus. Places that are not gringo-friendly may require use of Spanish, and patience. Just because a place is not gringo-friendly does not imply that the people there will not be friendly or that tourists will not be welcome.While the Mexican peso is the legal currency, US dollars are widely accepted. Tijuana observes daylight savings time (DST) the same way as the USA did pre-2007, from first Sunday in April to last Sunday in October. Note there will be several weeks each year when San Diego is on DST, but Tijuana is not. http://wikitravel.org/en/Tijuana