When I think of courageous people, I think:

Rosa Parks, who refused to give up her seat and triggered an end to segregation of public transport.
Edward Snowden, who knew he would face the death penalty, but exposed (yet more) government corruption.
Greta Thunberg, who, at a very young age, berated world leaders for failing future generations.
The guy at Xara, who rotated a square by 45° and announced it as a new tool.