Saw this on BBC yesterday 100 years ago Armenian Genocide occurred and did not know about it. Very sad time in history for human kind.

The mass killing of Armenians by Ottoman Turks during World War One remains a highly sensitive issue. Turkey has resisted widespread calls for it to recognise the 1915-16 killings as genocide, while historians continue to argue about the events. At the time there were numerous reports of Turkish atrocities committed against the Armenians.
The tragedy is in the news again because of commemorations marking the 100th anniversary.

There is general agreement that hundreds of thousands of Armenians died when the Ottoman Turks deported them en masse from eastern Anatolia to the Syrian desert and elsewhere in 1915-16. They were killed or died from starvation or disease.
The total number of Armenian dead is disputed. Armenians say 1.5 million died. The Republic of Turkey estimates the total to be 300,000.

According to the International Association of Genocide Scholars (IAGS), the death toll was "more than a million". In a letter to Turkish Prime Minister Recep Tayyip Erdogan in 2005 the IAGS said "we want to underscore that it is not just Armenians who are affirming the Armenian Genocide but it is the overwhelming opinion of scholars who study genocide".

Article Two of the UN Convention on Genocide of December 1948 describes genocide as carrying out acts intended "to destroy, in whole or in part, a national, ethnic, racial or religious group".

The dispute about whether it was genocide centres on the question of premeditation - the degree to which the killings were orchestrated. Many historians, governments and the Armenian people believe that they were; but a number of scholars question this.
Raphael Lemkin, the Polish-Jewish lawyer who coined the term "genocide" in 1943, referred to the atrocities against Armenians as well as the Nazi massacres of Jews when describing his investigations.

Turkish officials accept that atrocities were committed but argue that there was no systematic attempt to destroy the Christian Armenian people. Turkey says many innocent Muslim Turks also died in the turmoil of war.

The Young Turks - an officers' movement that had seized power in 1908 - launched a series of measures against Armenians as the Ottoman Empire was crumbling through military defeats in the war. The Young Turks - calling themselves the Committee of Unity and Progress (CUP) - had entered the war on Germany's side in 1914.

Turkish propaganda at the time presented the Armenians as saboteurs and a pro-Russian "fifth column".

Armenians mark the date 24 April 1915 as the start of what they regard as the genocide. That was when the Ottoman government arrested about 50 Armenian intellectuals and community leaders. They were later executed.
Armenians in the Ottoman army were disarmed and killed. Armenian property was confiscated.

Q&A: Armenian genocide dispute - BBC News