WWI and WWII were grave events in the history of Mankind, it changes everything both in warfare and the in lineage of some race in the World. What gave birth to Adolf Hitler's reason for the Holocaust was the annihilation of the one and half million Armenians before and during WWI; an evil conception to the Blood Thirsty Dictator which turns out killing over 6 Million and over 17 Million European Jews in total killed or mutilated during WWII.
"MAN'S INHUMANITY TO MAN"
In the Ottoman Empire, over 2 million Armenians were residing there before the "Ethnic Cleansing Genocide" by the Turkish Government which hid under the disguise of WWI and wiped out 1.5 Million lives with the aim; unification of through one religion(Islam) and one language for the Turkish people. This was the mass killing that prompted Hitler's in WWII to mass murder Jews since World powers never cared about the killing of the innocent Armenians. The Assyrians, Pontians, and Anatolian Greeks were also victims of the Armenian Genocide.
"I will give them a box on the ear that will make them relinquish their revolutionary ambitions"- Abdel Hamid II(The Bloody Sultan).
In the wake of fierce tension ensuing between Turkish authorities and Armenians late in the 18th century(1980), the Bloody Sultan fulfilled "Box on the ear" promise in 1894 with the first Armenian massacre killing over 8000 Armenians through the military and Ottoman forces assault on Armenian towns and villages. The following year, in Urfa Cathedral; 2500 Armenians women were torched to death not long after which 5000 Armenians were killed in a protest soliciting for international help as the mass killing on Armenians continued. They had a short relief when the Bloody Sultan was overthrown in 1909 by fresh and young Turkish Group referred to as "Young Turks". But the Armenians hope was shortlived after they experienced a bloodier quest from the Young Turks to develop and modernize the Turkish Government by establishing a more gripping rule in the surrounding territories of the Ottoman Empire. This they did by annihilating almost the remaining Armenian populace.
These they achieved in 1914 upon joining the World War, using the War as the perfect Cover to wipe the Armenians, the Turks Removed Armenians from war regions rendering them powerless by disarming them in case of self-defense. The Young Turks ordered a direct destruction of the Armenians in a secretly transmitted message which led to the armed arrest of Armenians Scholars, intellectuals, Politicians, Religious Leaders, Educators; 300 in Total on the 24th of April 1915 shooting and hanging them.
On April 24th, 1985, The United States declared the day as "National Day of Remembrance of Man's inhumanity to Man" in recognition of the 1.5 Million Armenians ancestry victims of the Turkish Genocide!