Well, according to me, heroism is nothing but to live for others and to keep yourself and the world happy. Everyone is a hero, from a sweeper out in the streets to a social worker. The image which we generally have in our mind when we hear the word hero (Something like Superman, Spiderman etc.) is not always true.
Coming to the second part of your question,
well its really very unfortunate but true that the real heroes are never acknowledged for the work they do.
Hope you liked my Answer. KEEP SMILING. :)