<P> The United Nations Educational, Scientific and Cultural Organization (UNESCO) World Heritage Sites are places of importance to cultural or natural heritage as described in the UNESCO World Heritage Convention, established in 1972 . Peru ratified the convention on February 24, 1982, making its historical sites eligible for inclusion on the list . </P> <P> The first sites within Peru were inscribed on the list at the 7th Session of the World Heritage Committee, held in Florence, Italy in 1983: "City of Cuzco" and the "Historic Sanctuary of Machu Picchu". As of 2010, Peru has 11 sites on the World Heritage List . Seven are listed as cultural sites, two as natural, and two as mixed, meeting both cultural and natural selection criteria, as determined by the organization's selection criteria . Only six of Peru's twenty - five regions are represented, with Ancash, Cuzco, and Lima regions each containing multiple sites . </P> <P> In 1997, a wildfire among the hills adjacent to Machu Picchu threatened the site until fire fighters could cut a ring of trees to prevent the fire from spreading to the ruins . In early 2010, heavy rainfall affected Machu Picchu and Cuzco . On January 25, 2010, 2,000 tourists were stranded near Machu Picchu when a landslide blocked the railroad connecting the site with Cuzco . The tourists were evacuated by ten helicopters, including four from the United States military on loan from the embassy in Lima . </P>

When was machu picchu listed as a world heritage site