Few sports are more dangerous than boxing. Although there is a risk of potential injury in any athletic endeavor, in the sweet science, hurting is the entire point.
There's a reason boxing people like to say, "You don't play boxing."
So even at moments of high drama and excitement, the shadow of terror can lurk. In the best of circumstances, the referees, ringside physicians and fighters' seconds all play their roles to prevent tragedy and keep this brutal sport still a sport.
And in compiling this list, I have omitted actual tragedies. The moments I'm detailing here were scary, but no significant long-term harm seems to have come from them.