Armenian Genocide Remembrance Day, also known as Armenian Genocide Memorial Day, is observed every April 24 in the Republic of Armenia and by the Armenian diaspora worldwide. This day commemorates the systematic extermination of Armenians by the Ottoman government during World War I, which began with the arrest of approximately 250 Armenian intellectuals in Constantinople on April 24, 1915. It is estimated that around 1.5 million Armenians were killed as a result of the genocide, making it one of the first genocides in modern history. The day was formally adopted as an official remembrance day in the Armenian Soviet Socialist Republic in 1988 and later declared a public holiday in independent Armenia. On this day, thousands gather at Tsitsernakaberd, the Armenian Genocide memorial complex in Yerevan, to honor the victims by laying flowers at the eternal flame, with similar ceremonies taking place in other Armenian cities and towns.