Unesco has warned Peru that the Inca citadel of Machu Picchu might lose its world heritage status if they do not act to protect it. Every year, hundreds of thousands of people visit Machu Picchu. Experts say unrestricted tourism and landslides have damaged the 15th Century citadel and the nearby Inca trail that leads to it. In response, the Peruvian authorities have submitted a 400-page report $130m plan to the UN’s cultural arm which is believed to include satellite monitoring to measure earth movements and a daily limit of 2,500 tourists, to preserve the site.