'Abd Allaah ibn 'Amr said,
"I went to the Prophet (صلى الله علیه وسلم) one day whilst he was performing Wudoo' (ablution) slowly and carefully. He raised his head, looked at me and said, 'Six things will happen to this Ummah: the death of your Prophet - 'and when I heard that I was aghast,' - this is the first. The second is that your wealth will increase so much that if a man were given ten thousand, he would still not be content with it. The third is that tribulation will enter the house of every one of you. The fourth is that sudden death will be widespread. The fifth is a peace-treaty between you and the Romans: they will gather troops against you for nine months - like a woman's period of childbearing - then they will be the first to break the treaty. The sixth is the conquest of a city.' I asked, 'O Messenger of Allaah, which city?' He said, 'Constantinople.' " [Ahmad] 
Abu Hurayrah said,
"The Prophet (صلى الله علیه وسلم) said, 'Hasten to do good deeds before six things happen: the rising of the sun from the West, the smoke, the Dajjaal, the beast, the (death) of one of you, or general tribulation.' " [Ahmad, Muslim] 
Hudhayfah ibn 'Ubayd said,
"The Prophet (صلى الله علیه وسلم) came upon us whilst, we were busy in discussion. He asked us, 'What are you talking about?' We said, 'We are discussing the Hour.' He said, 'It will not come until you see ten signs: the smoke, the Dajjaal, the beast, the sun rising from the West, the descent of Jesus son of Mary, Gog and Magog, and three land-slides - one in the East, one in the West, and one in Arabia, at the end of which fire will burst forth from the direction of Aden (Yemen) and drive peopl eto the place of their final assembly.' " [Ahmad] 
 Ahmad, Musnad, 2/174.
Checker's Note: Da`eef, Musnad Imaam Ahmad, checking by Ahmad Shakir: 6623. Weak hadeeth due to Abra Iamah al-Kalbi.
 Muslim, Kitaab al-Fitan, 8/207, Ahmad, Musnad, 2/337, 372.
 Muslim, Kitaab al-Fitan, 8/179.
Checker's Note: Wrong spelling, Ibn `Ubayd should be Ibn Usayd. Reported by Muslim, not by Ahmad as main text states.