Afflictions and the End of the World
Bukhari :: Book 9 :: Volume 88 :: Hadith 239
Narrated Anas bin Malik:
The Prophet said, "Ad-Dajjal will come and encamp at a place close to Medina and then Medina will shake thrice whereupon every Kafir (disbeliever) and hypocrite will go out (of Medina) towards him."