A video clip went viral on social media on Sunday showing a man climbing down the outside of an 11-storey apartment building in Hong Kong.

The video showed the man starting from the rooftop of the public housing building in Nam Shan Estate in Shek Kip Mei, Kowloon and using the railings on each floor’s external walkway to go all the way to the ground, news website HK01.com reported.

It took only 42 seconds for him to get from the roof of the building to street level.

The security guard of the building was reportedly shocked when he saw the video, saying that he did not know when it had happened and that he would report the case to the estate management office. Other residents also expressed concern over the man’s disregard for safety.

Police say they have not received any report on the matter.

Parkour is a type of urban acrobatics developed by a Frenchman and inspired by military obstacle course training.

It includes running, climbing, swinging and jumping unaided and without safety equipment.