Millions of tourists visit Peru's Machu Picchu citadel each year.

It is a World Heritage Site and it is increasingly under threat. Tourists leave behind more than five tonnes of rubbish every day.

In response, municipal authorities are trying to turn the area into the country's first eco-friendly zone.

Al Jazeera's Mariana Sanchez reports from the town of Aguas Calientes, the gateway to the citadel.