The word hero has such a diverse meaning, depending on the time setting and the circumstances. A great hero does not necessarily need a great cause. The littlest of things can be heroic to some but mean nothing to others.
I work as a lifeguard at a local lake community and last year our theme for our social event at the beach was "American Heroes". Each family made a poster to recognize a particular group of heroes. Some children had fathers who were firefighters and some had grandfathers who had served in the military. Others made signs in support of their favorite television or movie hero. There was only one, however, that touched me the most, and that was the poster that displayed each of the lifeguards' names in a yellow star and read "Lifeguards are our heroes!". I would have never though someone could see me, such an ordinary person, as a hero.
Clearly, one does not need greatness to be a great hero to someone.
Although most of our heroes are those who act in a heroic manner in times of distress, there definitely are peacetime heroes. Just as in the instance provided in the previous paragraph, heroes don't necessarily have to fix a problem, but can simply prevent them from occurring. There are many people who may not be thought of as heroes because they don't always act in manners that catch the public's eye. People like security guards, patrol officers, and lifeguards are heroes because they can play the role in protection and prevention. They keep the peace, so thus they are peacetime heroes.
Most people will think of a hero as masculine. Until more recently, women weren't really allowed to do much, so its not wonder most of our most famous heroes are...