Sahih Bukhari | Volume 3 | Hadith Number 102

Narrated by Usama
Once the Prophet stood at the top of a (looked out from upon one) castle amongst the castles (or the high buildings) of Medina and said, "Do you see what I see? (No doubt) I see the spots where afflictions will take place among your houses (and these afflictions will be) as numerous as the spots where rain-drops fall."