What are examples of people that have took action against a human right that was being violated?

The American abolitionists of the pre-Civil War era are an example.

Explanation:

Freedom is one basic human right. Both the Declaration of Human Rights and the Declaration of Independence recognize that all people have a right to their freedom just because they are human beings. In other words, this is a natural right that people are entitled to since the day they are born.

Slavery is therefore, a violation against this human right, and abolitionists, who were people against slavery in pre-Civil War americas, were thus examples of people who took action against a violation of a human right.