Four people in China’s northeastern Heilongjiang Province were stunned when the ground underneath their feet gave way as they stood waiting at a bus top.

A security camera recorded the moment at 5:40pm on August 22 on Guxiang Boulevard in Harbin. One woman is seen clinging to a pipe after the collapse, while another woman and two men fell to the bottom of the three meter-deep hole.

Just prior to the collapse, a crowd of people are seen walking through, indicating this could have been even worse.

Some people at the scene helped the victims get out of the ten square meter hole, while others on the stairwell simply watched and then walked away.

The victims were sent to a Harbin hospital where they were treated for various injuries including sprains and abrasions. Police cordoned off an area 100 meters around the sinkhole as workers attempted to make repairs.

There still has been no official word as to what caused the sinkhole, although an investigation is said to be pending. The hole was repaired the day after it appeared, and reports say business in the area has returned to normal.

Sinkholes in China have become a regular occurrence.

This past May, two pedestrians were injured when a  two meter-deep sinkhole appeared beneath their feet in Duchang, Jiangxi Province. Jiangxi also had another sinkhole back in March when three students were swallowed by a three meter-deep hole in Pingxiang.

In June 2013, a grandmother and her grandson were swallowed up by a three meter-deep hole in Shenzhen. In June 2010, a women was swallowed up by a hole in Chengdu after rains had been pelting the city for days.

Here’s the video of the incident in Harbin: