The Cerro de la Estrella National Park was established in 1938 and is considered to be the most important natural area in the eastern part of the Valley of Mexico. The park covers over and was established for recreational and cultural purposes. The hill (cerro) was the site of the Aztec New Fire ceremony, last performed in 1507. The park is also culturally important due to the annual Passion Play which is partially conducted on the summit of the cerro each year. The area is managed by the Secretaría de Agricultura y Recursos Hidráulicos, but it lost its original forest cover due to over-cutting of trees. The ecosystem now on the site consists only of planted eucalyptus and Pinus patula trees, along with insects and rodents. There are also problems with illegal building and farming in areas.