A child gets a burger: A major civil rights moment in Oklahoma

A land of contradictions from the outset, the United States was founded by slave owners who spoke passionately and eloquently about liberty, freedom, and justice for all. In the beginning, "all" was limited to men of European ancestry who were wealthy enough to own land. The Constitution's protections did not apply to most of the people living in America for most of America's history—at least not in full.

Women—about 50% of the population—were not included in the country's concept of "all," likewise millions of slaves—and for a long time, their offspring. Native Americans, the descendants of the original inhabitants of the United States, were commonly excluded from the promise of America, as were many immigrants, ethnic groups, and religious minorities.

Despite all the work that remains to be done, all of those groups and many others now enjoy freedoms that had to be won—won through the courts, through the court of public opinion, through mass demonstrations, through legislation, through boycotts, and in many cases, through martyrdom.

Fighting to expand the definition of "all" requires powerless people to challenge the power structures that benefit from keeping certain people locked in their status as second-class citizens. They often do it at great risk to their jobs, their reputations, their homes, and in many cases, their lives. Even so, brave advocates and activists fought the good fight in every state in America. Each state has a unique story to tell about the epic struggles for civil rights that were waged there, as well as those that continue to be waged. The following is a tiny sliver of their collective efforts.

Using a variety of sources, Stacker identified a defining moment for civil rights in all 50 states. They stand out for different reasons and led to changes that lifted different groups, but they all prove how much can be achieved—and how much still remains to be accomplished.

Keep reading to find out your state's contribution to civil rights.

Oklahoma: A child gets a burger

In 1958, 13 African American children ages 6-13 and their teacher, Clara Luper, sat in shifts for two days at a segregated lunch counter at Katz Drug in Oklahoma City. Refusing to leave until they'd been served, they were verbally abused, spit on, and had drinks, food, and even hot grease spilled on them by angry crowds until an employee caved in and served a hamburger to one of the children. The moment is remembered as one of the earliest uses of sit-ins as acts of nonviolent protest and civil disobedience.

Click here to see an event from every state or continue reading for other events near Oklahoma.

Arkansas: Little Rock 9 go to school

In 1957, three years after the Supreme Court struck down school segregation in the Brown v. Board of Education decision, nine African American students attempted to integrate Central High School in Little Rock, Arkansas. It took several tries—they were physically blocked on the first few attempts by a combination of enraged white mobs and armed National Guard troops. Finally, President Eisenhower federalized the National Guard, ordering them to escort the students to and from the building, and on Sept. 25, 1957, the Little Rock Nine began attending classes at Central High.

Colorado: A cultural rainbow gets results

Colorado's sizable population of not only African-Americans but also Native Americans, Mexican Americans, Roman Catholics, and Jewish immigrants all faced discrimination through the first half of the 20th century. Alone, these disparate underclasses did not have enough leverage to demand change—so they joined forces. A multiracial, multiethnic civil rights coalition protested and petitioned until the state passed a series of sweeping civil rights laws in 1957 to protect vulnerable minority groups, outlaw discrimination in housing and employment, and repeal bans on interracial marriage.