Each April 24, the thoughts of millions of Armenians, those who live in Armenia and the many more from across the world, turn to those who were killed in 1915.
On that date, around 300 intellectuals and community leaders were murdered. It is the official start of what Armenians claim was a genocide.
But the first massacres of Armenians had actually taken place in the late 19th century. Exiled groups of Armenians encouraged their compatriots in the Ottoman Empire to assert their nationalism.
Some 30,000 were killed – mainly by Kurds – in eastern Anatolia and thousands more died in Constantinople.
As the Ottomans fought Russian forces in eastern Anatolia during World War One, many Armenians formed partisan groups to assist the invading Russian armies.
In May 1915, Ottoman commanders began mass deportations of Armenians, to stop them from further helping the Russian enemy.
Hundreds of thousands were marched towards Syria and what is now Iraq. According to the Armenians, some 1.5 million died either in massacres or from starvation as they were forced through the desert.
Turkey estimates the number of Armenian dead to be 300,000 but said ethnic violence and the wider world war were to blame.
The modern Turkish republic was established in 1923 after the Ottoman empire collapsed.
Armenians are now one of the world’s most dispersed people and it is the diaspora which is at the forefront of efforts to convince the world to recognise the killings as genocide.
The Turkish penal code makes calls for this recognition illegal. And each time a country does formally acknowledge genocide against the Armenians – as France did last year – Ankara responds. In 2006 it suspended military ties with Paris.