A U.K ice climber is lucky to be alive after falling 100 feet down the side of a MOUNTAIN. He was wearing a helmet cam, so it's all on video.

You see the climber above him accidentally break off a big piece of ice. When he tries to avoid it, he loses his grip and starts sliding past rocks and snow. Then he keeps falling for another 30 seconds.

Doctors say his helmet saved his life. And the worst of his injuries was a broken ankle.