The statue of 17th century slave trader Edward Colston falls into the water after protesters pulled it down and pushed into the docks, during a protest in Bristol. Reuters

Once feted as pioneers, some of the architects of Europe’s empire building now face a backlash: anti-racism protesters are demanding their legacies be revisited and their often imposing statues be torn down and consigned to the trash heap of history.

From Cecil Rhodes in England and Captain James Cook in Australia to Christopher Columbus in the United States and King Leopold II in Belgium, the imperialists are under attack, sometimes from the descendants of those they once colonised.

A municipal worker used a high pressure water cleaner to remove the paint from the statue of Piet Hein in Rotterdam, Netherlands. AP

The cause? A sweeping global reassessment of history and racism triggered by the May 25 death of George Floyd, a black man who died after a Minneapolis police officer knelt on his neck for nearly nine minutes while detaining him.

“Slavery is still very real history for black people — we are still living with the consequences of it, with a racial hierarchy that puts black people at the bottom,” said Mary Ononokpono, who is doing a PhD at the University of Cambridge on the British-Biafran slave trade.

“Britain, Europe and America — and Africa — have to confront their history,” said Ononokpono. “We urgently need to have a long-overdue and honest discussion about the history of slavery and its legacy of impoverishment.”

Ballerinas Kennedy George, 14, and Ava Holloway, 14, pose in front of a monument of Confederate general Robert E. Lee. Reuters

British Prime Minister Boris Johnson said on Friday it was "absurd and shameful" that a statue of Winston Churchill was at risk of attack by activists, his strongest statement yet on growing protests against the legacies of past leaders.

Protesters pulled down a statue of Edward Colston, a 17th Century slave trader, in the English city of Bristol on Sunday and dumped it in the harbour. It has been retrieved and will be placed in a museum.

Workers remove a controversial statue of Captain John Fane Charles Hamilton from Civic Square in Hamilton. AFP

Such is the anger that the movement has broadened to target colonialists, monarchs and explorers, who in some cases destroyed or enslaved local populations across the world in the European scramble for empire and treasure.

It has also reignited debate in the United States over symbols associated with the South’s pro-slavery Confederacy.

Opponents of the symbols, including monuments, memorials and the Confederate flag, consider them emblems of slavery, racism and US xenophobia. Supporters say they represent the South’s heritage and culture, and serve as a memorial to Confederate casualties during the 1861-65 Civil War.

Activists hold placards as they attend a Black Lives Matter protest whilst standing on one of the Lion Statues in Trafalgar Square in London. AFP

Statues have long been toppled as the currents of history shift and empires rise and fall.

Just days after the American Declaration of Independence in 1776, revolutionaries felled a statue of George III. During the French Revolution, Louis XV was torn down.

Josef Stalin fell in Budapest in 1956 during the Hungarian Revolution. Vladimir Lenin was toppled as first the Berlin Wall and then the Soviet Union itself crumbled.

“Iron Felix” Dzerzhinsky, who established what became the KGB, was pulled down in 1991 outside KGB headquarters in Moscow. In Baghdad, Iraqi President Saddam Hussein’s statue was felled after the invasion in 2003, with the help of American troops.

Moscow even has a cemetery for fallen statues: a museum littered with the crumbling heroes of a fallen superpower.

While revolutions may usher in sharp changes in historical perspective, rarely has one man’s death triggered so much debate about racism and the sins of the past — which many black people feel have yet to be atoned for.

Some find the destruction of statues troubling.

A picture shows the vandalised statue of King Baudouin of Belgium in front of Saint Michael and Gudula Cathedral. AFP

Former Australian prime minister Tony Abbott condemned demands to take down a statue of Rhodes at Oxford University.

“Pulling down statues of past heroes is cultural vandalism of the worst sort,” Abbott, a Rhodes Scholar, told the Australian Financial Review. “We should learn from their strengths and their weaknesses but we should never imagine that we have the last word in wisdom and insight.”

New Zealand city on Friday took down a statue of a British navy commander accused of killing indigenous Maori people in the 19th century, as global debate swirls over monuments that represent racial oppression.

In Africa, too, there is caution.

Anthony Bouadi, 30, a tour guide at Cape Coast Castle in Ghana, where slaves were once held in windowless dungeons before being sent across the Atlantic, said it was wrong to tear down statues.

“They should have a specific museum for those monuments and statues — a museum that portrays the history of slave-owners,” Bouadi said.

“The history of the transatlantic slave trade is very cruel, it’s not a good thing. However, we have to remember what happened in the past so we don’t repeat what happened.”

In the United States, the modern movement to remove Confederate memorials began with the 2015 murder of nine black worshippers at a church in Charleston, South Carolina, by a white supremacist.

Outrage over the massacre prompted South Carolina’s governor to sign a bill enabling the removal of the Confederate flag from the State House grounds, and, according to a Southern Poverty Law Centre estimate, led to the removal of more than 100 other Confederate symbols.

Reuters