Over the course of 100 days in 1994, between 7 April and mid-July, up to a million people were killed in Rwanda, in a mass slaughter unparalleled in modern history.

It is believed that 800,000 people were killed in the first six weeks, at a rate five times higher than that of the Nazi Holocaust. Around one-fifth of the country's entire population was murdered. Most of the dead were Tutsis, and most of the killers were Hutus. This was genocide; a concerted effort to exterminate an entire group of people.

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Shelves of skulls are pictured at one of the many genocide memorials in RwandaReuters

The Tutsi minority were ruling caste, historically in control of the monarchy, the army and the administration. Resentment boiled over among Hutus, who made up 84% of Rwanda's population. In 1990, rebels of the Tutsi-dominated Rwanda Patriotic Front (RPF) invaded northern Rwanda from neighbouring Uganda.

The RPF's success prompted President Juvenal Habyarimana, a Hutu, to sign a deal with them to end years of civil war and allow power sharing. However, Habyarimana was slow in implementing the plan and a transitional government failed to take off.

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A Rwanda Patriotic Front (RPF) rebel soldier stares at a portrait of slain president Juvenal Habyarimana in KigaliCorinne Dufka/Reuters

On 6 April 1994, a plane carrying Habyarimana and Burundi's President Cyprien Ntaryamira was shot down in a rocket attack. Habyarimana's death triggered a 100-day orgy of violence, perpetrated mainly by Hutus against Tutsis and moderate Hutus. Hundreds of thousands of people were slaughtered by hand, using home-made weapons and household tools – knives, hammers and machetes. Tutsi families were blown up in churches where they had taken refuge.

Finally in July, the RPF – under the command of Paul Kagame – captured Kigali, and around two million Hutus fled to Zaire (now the Democratic Republic of Congo). Thousands of these refugees, who included those who carried out the massacres, died of dehydration and cholera.

The West largely stood by and ignored what was happening. When diplomatic messages warned the US, Britain and the United Nations of an imminent "new bloodbath" in February 1994, no action was taken. The UN finally agreed to increase its contingent of troops to 5,000, but they weren't deployed until after the killing had stopped.

IBTimes UK presents this harrowing series of photos illustrating the darkest days in recent history.

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9 April 1994: A Rwandan woman carries a Swiss family's baby at Butare on the boder with Burundi, as foreigners flee the violence in RwandaPascal Guyot/AFP
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11 April 1994: French paratroopers help Europeans at Kigali airport during an evacuation operationPascal Guyot/AFP
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12 April 1994: A French soldier accompanies a convoy of Europeans to the airport in KigaliReuters
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30 April 2004: Tutsi children play at a refugee campPascal Guyot/AFP
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3 May 1994: Refugees wait for relief food from the Red Cross near the border between Rwanda and TanzaniaReuters
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5 May 1994: Displaced Rwandans collect water from a polluted lake near a refugee camp in Benako, TanzaniaGerard Julien/AFP
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8 May 1994: Dead bodies lie along the side of a road about 70 kilometres north of the Rwanda/Tanzania borderCorinne Dufka/Reuters
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8 May 1994: Makeshift shelters are seen at a refugee camp in Benako, Tanzania, after torrential rainGerard Julien/AFP
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11 May 1994: A Canadian Military Police officer plays with refugee children at the Kigali sports stadium where they were living with around 20,000 Rwandans who fled their homesGerard Julien/AFP
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12 May 1994: Tutsi children who were mutiliated with machetes rest at the Red Cross hospital in KigaliGerard Julien/AFP
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20 May 1994: An amputee walks past three Tutsi refugees huddled together to protect themselves against the cold and damp in a camp in southern RwandaCorinne Dufka/Reuters
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20 May 1994: Fishermen pile up corpses for burial at Kasensero village in Uganda. The bodies were carried by the Akagera river from Rwanda into Lake VictoriaReuters
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23 May 1994: Rwandan Patriotic Front rebels load mortars and other ammunition onto a truck after taking the Kanombe barracks from government troopsCorinne Dufka/Reuters
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26 May 1994: Rwanda Patriotic Front rebels inspect the wreckage of the plane in which President Juvenal Habyarimana was killed when it crashed on 6 April, sparking the murder of hundreds of thousands of peopleCorinne Dufka/Reuters
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27 May 1994: Rwandan orphans cling to each other in a church in Kabgayi, a town about 65km south of KigaliAlexander Joe/AFP
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28 May 1994: Rwandan orphans hide in a house near their orphanage after it was hit by shellingCorinne Dufka/Reuters
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28 May 1994: A displaced Tutsi baby cries as she and her mother wait for food at a refugee camp in KabgayiAlexander Joe/AFP
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28 May 1994: Displaced Tutsis wait for food at Kabgayi refugee camp, south of the capitalAlexander Joe/AFP
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30 May 1994: Thousands of Rwandan refugees cross the border into Tanzania carrying their belongingsJeremiah Kamau /Reuters
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5 June 2004: An exhausted Rwandan mother lies next to her two crying children at Runango refugee camp about 50km south of the capitalAbdelhak Senna/AFP
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6 June 1994: A Tutsi Rwandan Patriotic Front fighter lights a cigarette in Nyanza in the Gitarama district of central RwandaAbdelhak Senna/AFP
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9 June 1994: A child with a gun sits in a car with Rwandan Patriotic Front partisans patrolling the streets of KigaliAbdelhak Senna/AFP
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12 June 1994: A young Rwandan government soldier holds his machine gun on the Mushubuti front line during the battle against Rwandan Patriotic Front rebelsAlexander Joe/AFP
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12 June 1994: A Rwandan government soldier takes aim in a banana field on the Mushubuti frontline as Rwandan Patriotic Front (RPF) rebels make gainsAlexander Joe/AFP
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13 June 1994: Three girls who were saved from Hutu militias by Rwandan rebels stand in a school which is now safely in rebel held territoryReuters
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22 June 1994: Rwandan youngsters carry water at Benako refugee camp in TanzaniaReuters
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22 June 1994: An elderly Rwandan refugee looks through a barbed wire fence at a UN mission in BenakoReuters
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23 June 1994: A little Hutu boy waits for his food rations, along with thousands of others living in the sprawling refugee camp in BenakoCorinne Dufka/Reuters
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27 June 1994: A French soldier shakes hands with Hutu children in the village of Murutu, 60 km from the border with ZairePascal Guyot/AFP
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27 June 1994: French soldiers pass Hutu troops from the Rwandan government forces near Gisenye, about 10km from the border with Zaire. The French military was later accused of ferrying extremist Hutu militiamen to a mountain hideout in Rwanda to slaughter thousands of ethnic TutsisPascal Guyot/AFP
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7 July 1994: A Rwandan Patriotic Front rebel examines a nail-spiked club found near a militia checkpoint which was abandoned after the rebels captured Kigali. Such weapons were used by the militia to slaughter of hundreds of thousands of Tutsis and opposition HutusCorinne Dufka/Reuters
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10 July 1994: A French paratrooper holds a Tutsi child in the western Rwanda village of RwimpiriPascal Guyot/AFP
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15 July 1994: A Zairean soldier with a bandana covering his face searches Rwandan refugees for weapons at the border crossingCorinne Duka/Reuters
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17 July 1994: A Zairean soldier steals from a Rwandan civilian before he crosses into the country, fleeing in front of advancing RPF forcesCorinne Dufka/Reuters
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18 July 1994: A Zairean soldiers inspects a pile of weapons left behind after Rwandan government troops fled the border city of GisenyiCorinne Dufka/Reuters
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19 July 1994: An elderly Rwandan refugee, exhausted and starving , is carried by relatives to a refugee camp near Goma airport in ZairePascal Guyot/AFP
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19 July 1994: Rwandan refugees cross the Zairean border at Goma to flee RPF troops advancing on the town of GisenyiPascal Guyot/AFP
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19 July 1994: Rwanda's newly-elected Hutu president Pasteur Bizimungu and his vice president the Tutsi-led RPF (Rwandan Patriotic Front) commander Paul Kagame, share a joke in KigaliPascal Guyot/AFP
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20 July 1994: A Rwandan refugee girl stands next to a mass grave outside Kigali, where dozens of bodies were laid to restCorinne Dufka/Reuters
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22 July 1994: A young Rwandan boy waits for his ration of water in a refugee camp near Goma in ZaireVincent Amalvy/AFP
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23 July 1994: A dying Rwandan woman tries to breastfeed her child next to hundreds of corpses waiting to be buried at a mass grave near the Munigi refugee camp in Zaire, where thousands of refugees succumbed to cholera or dehydrationCorinne Dufka/Reuters
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23 July 1994: An aid truck full of medical supplies makes its way past scores of bodies of Rwandan refugees who died of choleraCorinne Dufka/Reuters
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24 July 1994: A Rwandan refugee carries his child on his shoulders on his return from Goma in ZaireVincent Amalvy/AFP
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26 July 1994: A little girl suffering from cholera is carried past the bodies of hundreds of Rwandans in the Mugunga camp in ZaireCorinne Dufka/Reuters
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26 July 1994: Rwandan children suffering from dysentery are given milk at an orphanageUlli Michel/Reuters
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28 July 1994: Rwandan refugees carry food distributed by the Red Cross at the Kibumba camp in ZaireUlli Michel/Reuters
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28 July 1994: A Rwandan woman collapses with her baby on her back along a road connecting Kibumba refugee camp and Goma in Zaire. Aid officials said that refugees were dying at a rate of 1,800 per dayUlli Michel/Reuters
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29 July 1994: A Rwandan refugee carries the body of his baby who died of cholera towards a mass graveCorinne Dufka/Reuters

Every year, on 7 April, millions of people in Rwanda hold events to pay homage to the victims of genocide.