Sahih Bukhari Volume 001, Book 003, Hadith Number 080.

Narated By Anas : Allah's Apostle said, "From among the portents of the Hour are (the following):

1. Religious knowledge will be taken away (by the death of Religious learned men).
2. (Religious) ignorance will prevail.
3. Drinking of Alcoholic drinks (will be very common).
4. There will be prevalence of open illegal sexual intercourse.