The Prophet Muhammad is believed to have said that "the last hour will not come" until Muslims vanquish the Romans at "Dabiq or Al-A'maq" - both in the Syria-Turkey border region - on their way to conquer Constantinople (modern-day Istanbul).
many of IS films have been signed off with an image of an IS fighter walking slowly across a landscape carrying a large black banner accompanied by an audio clip from the former leader of the group, Abu-Mus'ab al-Zarqawi, mentioning Dabiq.
Al-Zarqawi, who was killed in a US air strike in Iraq back in 2006, is heard to say: "The spark has been lit here in Iraq, and its heat will continue to intensify... until it burns the crusader armies in Dabiq".
That quote dates back to September 2004 - a few days before Al-Zarqawi's group captured a Briton and two American hostages who were later beheaded.
It has since been used extensively in Dabiq magazine, whose launch in July signalled a clear intention to use the apocalyptic imagery to reach out to an international audience.
http://www.bbc.com/news/world-middle-east-30083303