5 American heroes you know, and the 5 ways they fought for freedom you might not know about.

Ah, 4th of July. Freedom is in the air.

Can you smell it? GIF from "The Colbert Report."

The U.S. has a rich history of separate movements that have worked together to create a better country for its citizens. But sometimes it seems we forget that these movements do not occur in silos; they're often intertwined — and even share some activists!

So, before you fire up your grill and share some drinks with family and friends, let's take a second to have a quick (but fun!) history lesson, shall we?

Here are five not-so-well-known causes that were supported by well-known freedom fighters:

1. Rosa Parks refused to give up her seat on the bus, but she was also an anti-rape advocate.

Image from the White House.

During her time as chapter secretary of the Montgomery, Alabama, NAACP, Rosa Parks served as an sexual crimes investigator and was heralded as one of the best. She continued to speak out and fight the systemic abuse of black women outside her role as well, helping black women find justice against white rapists in a time when justice was near impossible to get.

While we've come a long way, the fight against rape culture is still going strong. Check out some of the groups working to create a world free of sexual violence at the National Alliance to End Sexual Violence and the National Sexual Violence Resource Center.

2. Helen Keller advocated for the rights of people with disabilities, but she also supported increased birth control access.

Photo by Topical Press Agency/Getty.

The deaf and blind activist best known for her work in disability rights also supported a myriad of other causes. Many people don't know that she a passionate advocate for women's access to birth control. Or, to put it in her words, which are delightfully blunt:

"Only by taking the responsibility of birth control into their own hands can [women] roll back the awful tide of misery that is sweeping over them and their children."

#realtalk, amirite?

I can't believe that I'm writing this in 2015, but ... the fight for reproductive rights is still raging on. Check out these organizations that are carrying on the fight for increased access to birth control and comprehensive sex education: Advocates for Youth and the Center for Reproductive Rights.

3. Dr. Martin Luther King Jr. gave his famous, "I Have a Dream" speech, but he also focused on the importance of equal economic opportunity for all.

Image via Minnesota Historical Society/Flickr.

"True compassion is more than flinging a coin to a beggar; it is not haphazard and superficial. It comes to see that an edifice which produces beggars needs restructuring."

Dr. King dreamed of a world where people of different races could coexist peacefully. But he also knew how having equal economic opportunity for all Americans is vital to creating a more just society.

If you want to get in on the action to increase economic opportunity for Americans, check out Jobs with Justice and the Center for American Progress Talk Poverty project.

4. Susan B. Anthony fought for women's suffrage, but she started out as a slavery abolitionist activist.

Image from History of Woman Suffrage/Wikimedia Commons

"Extend to him all the rights Citizenship. Let him vote and be voted for; let him sit upon the judge's bench, and in the juror's box. ... Let the North thus prove to the South, by her acts, that she fully recognizes the humanity of the black man."

Anthony grew up with parents who were active in the antislavery movement of the 1840s. She followed in her parents' footsteps when she became an agent for the American Anti-Slavery Society. She also loved to write scathing op-eds denouncing lynchings and other racist acts against African-Americans in the local newspapers.

The fight for racial equality continues today, and it's far from over. Check out the Black Lives Matters movement (started by women, no less!) to see what you can do in the continued crusade for racial justice.

5. Cesar Chavez didn't only care about humans. He was also an avid animal rights supporter.

Image from Movimiento/Wikimedia Commons

"The basis for peace is respecting all creatures. We cannot hope to have peace until we respect everyone — respect ourselves and respect animals and all living things."

Chavez is best known for his leadership in the movement for farm workers' rights. But he also believed that the commitment to justice should include respect and love of animals. He really was about practicing what he preached: Chavez spent the last 25 years of his life not eating meat and even spent a few years as a vegan. Who knew?

If you're also all about helping our furry friends, definitely check out the American Society for Prevention of Cruelty to Animals and the Humane Society of the United States.

Now go impress your friends at the BBQ this weekend with your impressive historical knowledge.

Happy 4th!