Huge boulders land on cars on southern China highway

Massive boulders roll down a hill, striking vehicles on a highway in southern China's Chongqing on April 7.

The dash-cam video shows rocks tumbling down a hill, sending the smoke into the air and falling onto passing cars.

Other eye-witness video shows the scene on the road.

Two cars were damaged but no one was injured.

Police and firefighters were sent on site to clear the road and traffic was able to return back to normal.

The cause of the boulders falling was not known.