This article is more than 6 years old

This article is more than 6 years old

It has survived five centuries of conquest, earthquakes, landslides and mass tourism. But Peruvian authorities fear that Machu Picchu is facing a new threat: streakers.

Guards at the vast Inca citadel have been ordered to step up surveillance after a spate of stripping. Late last year, two male antipodean travellers were detained by guards after baring their backsides at the site – but not before a picture of their exploits went viral on Peruvian social media.

More recently, a video emerged on YouTube showing a couple streaking across the citadel's principal plaza as a park guard gave chase.

The incidents have provoked a prickly response from authorities in Cusco, the imperial city of the Incas, a train ride from the ruins.

Its new regional director of culture, Ricardo Ruiz Caro, announced that park guards would increase surveillance to "avoid these unfortunate events that threaten cultural heritage" while remarking pointedly that the incidents took place before he took charge.

A local travel agency obtained the handwritten police report on the incident last year, which details how the pair, a 30-year-old New Zealander and an 18-year-old Australian, were briefly taken into custody and told to erase the offending images from their camera before they were released. Somehow, the pictures still found their way on to the web.

"They were made aware that it is totally forbidden to take photographs of this magnitude," the report details.

It is possible that travellers have long felt the urge remove their clothes at Machu Picchu – perhaps inspired by its dramatic setting and history of spiritual ceremony.

Like many such trends, though, stripping at historic world monuments appears to have been given fresh impetus by the internet: blogs, YouTube and Facebook pages have given a new platform for naturist evangelists – and mere show-offs.