that is home to four types of vegetation: deciduous tropical forest, gallery forest, heath vegetation, and secondary vegetation. In addition to introduced species, there are many native species of flora and fauna. The canyon is studied by national and international researchers as it contains great biological diversity due to its geographical location. On June 5, 1997, it was declared a Protected Natural Area, as an Area Subject to Ecological Conservation (Zona Sujeta a Conservación Ecológica). La Cascada Cola de Caballo (The Horse Tail Waterfall) is located on the Guadalajara to Zacatecas road (Highway 54, km 15) a few kilometers from the Northern Peripheral, just after passing the village of San Esteban. The waterfall is fed by a stream from the Atemajac Valley. It is close to Guadalajara and a town with very little development, and as a result of poor ecological practices, it is very polluted. El Bosque los Colomos, the Colomos Forest, is located in the northwestern part of Guadalajara along the Rio Atemajac. It is in a wealthy part of the metropolitan area, and has been developed for recreation rather than being preserved in its wild state. The river was once one of the main sources of water supply to the city, and today continues to provide water to some surrounding colonias (neighborhoods). Currently, this forest covers an area of in which pine trees, eucalyptus trees, and cedars predominate. The park has jogging tracks, gardens (including a Japanese garden), ponds, a bird lake, instructional areas for school field days, playgrounds, camping areas, and horses to ride. Other places of interest around Guadalajara include Camachos Aquatic Natural Park, a commercial water park, and Barranca Colimilla, a beautiful canyon with hiking trails near Tonala, east of Guadalajara. Urbanism Guadalajara's street plan has evolved over time into a radial urban plan, with five major routes into and out of the city. It is surrounded by ring roads. The original city of Guadalajara was planned on a grid, with north–south and east–west intersecting streets. Over time, villages surrounding Guadalajara were incorporated into the city - first Analco to the southeast, then Mexicaltzingo to the south, Mezquitan to the north, and San Juan de Dios to the east, all of which introduced more variety to the plan. As it grew towards the west, it kept the original north–south orientation. As it grew towards the east, this grid was tilted towards the south-east to