Sayyiduna Hudhayfah bin Asid (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings be upon him) looked in on us while we were discussing the Hour, and he (peace and blessings be upon him) said: "The Hour will not be established until there are ten signs: the rising of the sun from the west, the Smoke, the Dajjal, the Beast of the Earth, and three sinkings of the earth: in the east, in the west, and in the Arabian Peninsula, the descent of Isa bin Maryam (peace be upon him), the opening of Ya'juj and Ma'juj, and a fire that will come out of the depths of Aden and drive the people towards the place of gathering."
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 3016