Not too many days ago, while I was busy doing what I have been known to do best recently – procrastination – I came across a very interesting video which led me, after some research, to want to write this article. The video in question was of Marlon Brando winning the Oscar for Best Actor for his role in The Godfather. It was the year 1973, a date that will forever be etched in Oscar history, not only because one of the most prominent actors of all time turned down an Oscar (that's right, turned down an Oscar!) – but more importantly, because of why and how he did it. It was a political act that caused a lot of talks. But along with it, there have been many others. So many celebrities have appeared on the Oscar stage with the sole aim of raising public awareness of situations and issues that they cared about. In this article, I would like to look back at some of these moments.

1940: Making history with Hattie McDaniel

Well, what can I say... In an environment dominated by only white people, in 1940, Hattie McDaniel completely rewrote Oscar history. She was in fact the first black woman to win – thanks to her performance in Gone with the Wind – the statuette for Best Supporting Actress.

1973: Sacheen Littlefeather rejects Marlon Brando's Oscar

"Hello. My name is Sacheen Littlefeather," she says, turning down the statuette brought to her by Roger Moore. "I'm Apache and... I’m representing Marlon Brando this evening, and he has asked me to tell you in a very long speech that I cannot share with you presently, because of time… but he very regretfully cannot accept this very generous award. And the reasons for this being are the treatment of American Indians today by the film industry". More memorable than winning an Oscar is undoubtedly its rejection, and Marlon Brando managed to do so in a way that is still remembered today.

1978: Vanessa Redgrave's speech

Of all the political speeches at the Oscars, Vanessa Redgrave's was probably the most controversial. The actress, after winning the Best Supporting Actress award for Julia, took the opportunity to share what had happened to her that night, when she was pilloried by members of the Jewish Defense League. Her speech, in which she made it clear that she would continue to fight against anti-Semitism and fascism, cost her years of criticism and outrage.

1994: Tom Hanks pays tribute to AIDS victims

After playing the part of a man with AIDS in the film Philadelphia, thanks to which he won his first Oscar in 1994, Tom Hanks wanted to pay tribute to the many victims who are affected by this disease every year. "I know that my work, in this case, is magnified by the fact that the streets of heaven are too crowded with angels," Hanks said. " We know their names. They number a thousand for each one of the red ribbons that we wear here tonight."

2003: Michael Moore against George Bush Sr.

Accepting the award for best documentary for Bowling for Columbine, Michael Moore decided he wanted to set out his opinion – and probably that of many others – on George Bush Sr.'s policies regarding the recent disastrous US invasion of Iraq. "We are against this war, Mr. Bush! Shame on you, Mr. Bush! Shame on you!" shouted Moore, who, before he could finish his speech, was abruptly interrupted by the orchestra.

2015: Patricia Arquette and equal pay

Patricia Arquette, picking up her Oscar for Best Supporting Actress for her role in Boyhood, wanted to send out a strong and clear message from a purely feminist perspective: "We have fought for everybody else’s equal rights. It’s our time to have wage equality once and for all and women’s rights for everyone in America."

2016: The threat of climate change

Leonardo DiCaprio's is probably one of the speeches that – to this day – almost everyone remembers, and this is not only because it was about a very current and important issue, but also because it was his first speech for winning the Oscar as Best Actor in a Leading Role for The Revenant. "Climate change is real. It is happening right now," DiCaprio said. "It is the most urgent threat facing our entire species, and we need to work collectively together and stop procrastinating."

2019: Rami Malek defends immigrants

Collecting the Best Actor in a Leading Role award for his portrayal of Freddie Mercury in the movie Bohemian Rapsody, Rami Malek wanted to send a message in favor of immigrants: "We made a film about a gay man, an immigrant, who lived his life just unapologetically himself," Rami Malek said, accepting the Oscar. "I am the son of immigrants from Egypt. I'm a first-generation American. Part of my story is being written right now, and I could not be more grateful to each and every one of you."

2019: Spike Lee urges people to vote

"Four hundred years [ago], our ancestors were stolen from all over Africa and brought to Jamestown, Virginia, enslaved. Before the world tonight, I give praise to our ancestors who helped build this county," Lee said, as he picked up the award for best-adapted screenplay for BlacKkKlansman. "The 2020 presidential election is around the corner. Let's all mobilize, let's all be on the right side of history. Make the moral choice between love versus hate. Let's do the right thing!"

2020: Joaquin Pheonix on injustice

When Phoenix was called on stage to collect his award for Best Actor in a Leading Role for the movie Joker, he took the opportunity to speak out on behalf of those he called "the voiceless". "I’ve been thinking a lot about some of these distressing issues that we are facing collectively, and I think sometimes we feel or are made to feel that we champion different causes. But for me I see commonality," Phoenix said. "I think whether we’re talking about gender and equality, or racism, or queer rights, or indigenous rights, or animal rights, we’re talking about the fight against injustice. We’re talking about the fight against the belief that one people, one race, one gender, one species has the right to dominate, control, use, and exploit another with impunity." As a climate activist, he added: "We feel entitled to artificially inseminate a cow and then steal her baby, even though her cries of anguish are unmistakable."