People often see professional athletes as being invincible -- supermen on the field as well as off. It's easy to forget these men are mere mortals.

Amazing professional athletes are sometimes taken from us too soon. Freak accidents, personal demons, lingering health issues or just reckless behavior -- some athletes meet their end in the prime of their career or shortly after their retirement. Whatever the reason, their deaths rocked the sports world.

Here's a look back at some of the most tragic and talked about deaths in sports history: