Of the Europeans who scrambled for control of Africa at the end of the 19th century, Belgium's King Leopold II left arguably the largest and most horrid legacy of all.
Former BBC Kinshasa correspondent
While the Great Powers competed for territory elsewhere, the king of one of Europe's smallest countries carved his own private colony out of 100km2 of Central African rainforest.
King Leopold II left arguably the largest and most horrid legacy
He claimed he was doing it to protect the "natives" from Arab slavers, and to open the heart of Africa to Christian missionaries, and Western capitalists.
Instead, as the makers of BBC Four documentary White King, Red Rubber, Black Death powerfully argue, the king unleashed new horrors on the African continent.
Torment and rape
He turned his "Congo Free State" into a massive labour camp, made a fortune for himself from the harvest of its wild rubber, and contributed in a large way to the death of perhaps 10 million innocent people.
What is now called the Democratic Republic of Congo has clearly never recovered.
"Legalized robbery enforced by violence", as Leopold's reign was described at the time, has remained, more or less, the template by which Congo's rulers have governed ever since.
Meanwhile Congo's soldiers have never moved away from the role allocated to them by Leopold - as a force to coerce, torment and rape an unarmed civilian population.
As the BBC's reporter in DR Congo, I covered stories that were loud echoes of what was happening 100 years earlier.
The film opens with the shocking images of some of Leopold's victims - children and adults whose right hands had been hacked off by his agents.
Men who failed to bring enough rubber for agents were killed
They needed these to prove to their superiors that they had not been "wasting" their bullets on animals.
This rule was seldom observed as soldiers kept shooting monkeys and then later chopping off human hands to provide their alibis.
Director Peter Bate uses documented accounts of such atrocities to present an imaginary court case against the monarch who he compares to a subsequent European tyrant, Adolf Hitler.
He has an actor play the bearded, heavily-set Leopold, fidgeting nervously as damning testimonies are read out, compiled by the foreign correspondents of the day, the missionaries.
John Harris of Baringa, for example, was so shocked by what he had come across that he felt moved to write a letter to Leopold's chief agent in the Congo.
"I have just returned from a journey inland to the village of Insongo Mboyo. The abject misery and utter abandon is positively indescribable. I was so moved, Your Excellency, by the people's stories that I took the liberty of promising them that in future you will only kill them for crimes they commit."
In the film's most powerful sequences we see reconstructions of the terror caused by Leopold's enforcers and agents.
We see a village burnt without warning and its people rounded up; its men sent off into the forests, and its women tied up as hostages and helpless targets of abuse until their husbands return with enough wild rubber to satisfy the agent.
This, we are told, was the "moment of truth" for the whole community.
If the men did not bring back enough and the agent lost his commission, he would order the deaths of everyone.
There is no doubt that Congo's history, and White King, Red Rubber, Black Death are almost too upsetting to bear, however Leopold did leave, albeit unwittingly, one positive legacy - the birth of modern humanitarianism.
Children and adults had their hands chopped off
The campaign to reveal the truth behind Leopold's "secret society of murderers," led by diplomat Roger Casement, and a former shipping clerk ED Morel, became the first mass human rights movement.
Its successors like Amnesty International, Human Rights Watch and the Kinshasa-based Voix des Sans Voix and Journaliste En Danger mean abuses in modern day DR Congo can never be hidden for long.
Congo: White king, red rubber, black death will be shown on BBC Four in the UK on Tuesday, 24 February at 2100