Video: Giant Sinkhole Swallows Woman As She Strolls Down Sidewalk

Surveillance footage has captured the moment a woman was swallowed by a sinkhole while walking down the street in China's Gansu Province on Sunday.

The woman, whose identity remains unknown, suffered fractured ribs and was rescued by local police in Lanzhou City. That's according to English-language state broadcaster CGTN, which posted a video of the incident to its Facebook page. The cause of the sinkhole remains unclear.

One video shows the victim, dressed in black, plunging into the ground as the earth opens up beneath her. A second clip, seemingly taken on a mobile device, shows the woman's moving leg as people peer over the edge of the hole. A third shows her in the hands of paramedics.

Australia's ABC News reported that the sinkhole was roughly 10ft wide and 10ft deep. The news outlet said the woman was helped out of the ground by authorities via a rope. Video showing the collapse quickly spread across Chinese social networking site Weibo.

The CGTN Facebook upload alone has attracted more than 800,000 views to date. The clip was obtained and widely shared by Reuters yesterday.

The timestamp on the surveillance footage shows the incident happened just before 6 p.m.

In October, four people were killed after a sinkhole opened in China's Sichuan province. The incident was recorded by a shop's CCTV camera and showed people tumbling into a 10ft pit. As previously reported, firefighters were seen scrambling for their lives during a second collapse.

What is a sinkhole?

The United States Geological Survey says on its website that a sinkhole is "a depression in the ground that has no natural external surface drainage." It explains: "This means that when it rains, all of the water stays inside the sinkhole and typically drains into the subsurface.

"When water from rainfall moves down through the soil, these types of rock begin to dissolve. This creates underground spaces and caverns. Sinkholes are dramatic because the land usually stays intact for a period of time until the underground spaces just get too big. If there is no support for the land above the spaces, then a sudden collapse of the land surface can occur."