What makes a hero?

This morning, I heard in the news that Neil Armstrong has died. To most American, Armstrong was and is a hero.
I won't say anything against Mr. Armstrong - what he did was certainly remarkable. But does being the first man on the moon make you a hero?
In my opinion, not.
A hero for me is someone who does not look for personal profit, who does not think one second before doing something which can save another one's life.
A real hero for for is the boy (only 10 years old) who was cycling with his little sister. The little girl bumped against a tree branch lying on the cycle path, and fell. Not just into the grass, but into the deep water of a river.
Her brother did not hesitate one second, but jumped off his own bike and into the water. He was able to find his sister in the dark water and tried to hold her head up. In the meantime, other people had alerted the 101 services and help was under way. Some adults helped the boy get out of the water, because that was something he could not do himself, and grabbed hold of the little girl.
She made it, and I should think she will thank her brother greatly.