Yearly visits to Machu Picchu, Peru's top tourist destination, have more than doubled since 1998 to 800,000 people, and conservationists warn that landslides, fires and creeping development threaten the site.

During the floods of 2010, heavy rains triggered mudslides, which swept away infrastructure, and the Peruvian military had to evacuate 4,000 people.

Recent weather patterns in the area have lurched from drought to heavy rains threatening the unique citadel

In Inca times, archeologists approximate that no more than 750 people lived in Machu Picchu at once. Today, more than 5,000 visitors pass through per day.