Tourists in Iceland were admiring a glacier when a massive chunk of it collapsed into the water right before their eyes.
The break triggered a huge wave that came rushing their way, prompting them to run away in fear.
The owner of an Icelandic tour company captured the whole thing on camera.
He said he could hear the crackling from the far-off glacier, which is a sign of calving.
Calving is when a large section of a glacier breaks off. It's usually caused by the glacier expanding.
None of the tourists were hurt.
VIDEO: Massive glacier chunk collapses into water in Iceland, sends tourists running in fear
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