“BLACK Lives Matter” is an awe-inspiring and powerful mantra for people protesting police violence against African-Americans.

Placards bearing those three words, alongside symbolic pictures of clenched fists raised in the air, are being brandished at protests worldwide after the death of George Floyd in the US.

If you see any protests against racism, chances are you'll notice demonstrators raising their arms skyward, while clenching their fists in unison.

The history of the symbolic gesture goes back decades, to show defiance and is often associated with both left-wing politics as well as oppressed groups, explains ABC News.

The black power movement used it as a gesture to represent the struggle for civil rights back in the 1960s.

And the Black Panther Party has long used it as a symbol of resistance.

In the sporting world, US runner John Carlos made history by raising a black-gloved fist on the podium at the 1968 Olympics to protest against racism.

A bronze medallist in the 200 metre sprint in Mexico City in 1968, Carlos joined the gold medallist, fellow black American Tommie Smith, in raising his fist and bowing his head on the podium while America's national anthem was playing.

The men’s protest against racism and in favour of “black power” marked a milestone in the civil rights movement in their home country and is an iconic image in Olympic history.

John Carlos later explained to Le Monde: “When you make that kind of public declaration, you send a message of courage to the world.”

These days, raised fists are also strongly associated with the Black Lives Matter movement's fight against racism.

Black Lives Matter was founded by three women who popularised the slogan during protests over the 2012 killing of Trayvon Martin, an African-American teen who was shot by George Zimmerman, a neighbourhood watch volunteer in Sanford, Florida.

Zimmerman was acquitted of second degree murder and manslaughter.

The Black Lives Matter movement began with the hashtag #BlackLivesMatter on social media, and grew into a nationwide movement in response to the use of excessive force by police, particularly against black men.

Its website explains that BLM "is a global organisation in the US, UK, and Canada, whose mission is to eradicate white supremacy and build local power to intervene in violence inflicted on Black communities by the state and vigilantes."

Before the clenched fists became synonymous with the movement, however, raised hands were seen at rallies to symbolise the "hands up, don't shoot" slogan.

Khanya Dalton wrote about this gesture in a column for The Black & White, the student news website for Walt Whitman High School in Maryland, US.

Dalton explains that the “hands up, don’t shoot slogan, along with the accompanying gesture of raising one’s hands above his or her head, became one of the core symbols of the Black Lives Matter movement after unarmed 18-year-old Michael Brown was fatally shot by a police officer [in Missouri], in August 2014.

"Brown reportedly was holding his hands above his head and mouthing the words 'don’t shoot' as the fatal shot was fired; while this claim was later debunked, the image has stuck.

"Since [then], the mantra has been used in protests against police brutality around the country."

The "hands up, don't shoot" gesture has recently been seen at rallies along with the clenched fist gesture in the wake of the brutal death of George Floyd - an unarmed black American who died in police custody in Minneapolis.

Video showed a white Minneapolis police officer kneeling on Floyd’s neck for nearly nine minutes before he died.