We generally have a pretty good idea of when we're in danger; but, paradoxically, it's when you're the most comfortable that you should be the most careful. In this video, we see a crowd of onlookers gathered to watch the launch of a new, heavy-duty ship tethered to the dock.

Unfortunately, a lot of people underestimate the truly terrifying power of snapback and the kinds of forces high-tension ropes/cables can unleash -- many of the folks in this video are standing unknowingly in the line of fire for any potential mishap.

Fortunately, instead of a quick trip to the afterlife all they got was a lesson in physics, watching an immensely heavy dock bollard get hurled through the air like a bullet, narrowly missing a nearby boat and creating a cannon-ball-like splash. Had the bollard stayed and the rope snapped, it's possible it could have whipped around and samurai-sworded everyone there like a field of wheat.