Nogales is served by Nogales International Airport. The population growth is in part due to the influx of industry that has come since the opening of the maquiladora industry through the National Industrialization Program, decades before the North American Free Trade Agreement (NAFTA). During the 90s, this economic context was, in part, held by an important Sonora state social policy by the Secretary of Urban Infrastructure and Ecology, Vernon Perez Rubio, accomplishing the city's total coverage on drinking water, with a 20-year guaranteed service. Manufacturing now accounts for 55% of the city's gross domestic product, and services are growing as well, most of this caused by the growing jobs in the city. Nogales is known for its recent enormous population growth which covers the hills along the central narrow north-south valley. Dispersed among the houses, the visitor will find a mixture of factories, stores, etc. In 2006, the southern half of the city experienced a modern urbanization development including shopping malls, wide avenues, and modern housing conglomerations. At the center of Nogales, there is the Plaza de Benito Juárez. Here there is a statue with two leading figures designed by Spanish sculptor Alfredo Just. This is a tribute to Mexican President Benito Juárez, and the other is the "Monument to Ignorance", where a naked man who represents the Mexican people is fighting with a winged creature that represents ignorance. The primary commercial artery is Mexico Federal Highway 15, which links the state with the U.S. as well as major cities in Mexico. In aviation, the city is served by the Aeropuerto internacional de Nogales, which, had no commercial airline service. Due to its location, Nogales is one of the most important ports of entry for U.S. tourists. The downtown area consists of bars, hotels, restaurants, and a large number of curio stores, which sell a large variety of artesanias (handicrafts, leather art, handmade flowers, clothes) brought from the deeper central and southern states of Mexico. Local dishes commonly available in restaurants include many types of antojitos (Mexican food) such as enchiladas, tacos, burritos with carne machaca (dried meat), menudo and tamales. Maquiladoras, or manufacturing plants, employ a large percentage of the population. Nogales' proximity to the U.S. and the abundance of inexpensive labor make it an efficient location for foreign companies to have manufacturing and assembly operations.