Qatida reported that Anas b. Malik said:
May I not narrate to you a hadith which I heard from Allah's Messenger (sallallaahu alayhi wa sallam) which no one would narrate to you after me who would have personally heard it from him (the Holy Prophet) (as I have the good fortune to do so)? -" It is from the signs of the Last Hour that knowledge would be taken away, ignorance would prevail upon (the world), adultery would become common, wine would be drunk, the number of men will fall short and the women would survive (and thus such a disparity would arise in the number of men and women) that there would be one man to look after fifty women.
Sahīh Muslim Hadīth No. 2671
Abu Hurayra reported that the Messenger of Allah, may Allah bless him and grant him peace, said, "The Final Hour will not come until people compete with one another in the height of their buildings."
al-adab al-mufrad Hadīth No. 449