Do you know anyone who is a hero? Or has done something extremely heroic?

For an essay, I am trying to provide examples of a hero and am finding it surprisingly difficult. Upon searching this question into google I have been confronted by various definitions of a hero, and a list of celebrities whom to my knowledge have never been exceptionally brave in their lives. I am looking for true heroes who have done something truly amazing to deserve recognition, for example people who have fought for their country or been extremely charitable. Thanks for your help!