Many times verses in the Quran repeated about the end of world. The question is when will be the end of world?
When the horn is blown once. The earth and the mountains will be carried off and crushed; utterly crushed. That is the day when the inevitable event will come to pass (Quran, 69:13-15)
The Quran promised that at the end of world, the deads would be awaken again for Judgement.
And they say, “There is not but our worldly life; we die and live (i.e. some people die and others live, replacing them) and nothing destroys us except time.” And they have of that no knowledge; they are only assuming. And when Our verses are recited to them as clear evidences, their argument is only that they say, “Bring [back] our forefathers, if you should be truthful.” Say, “God causes you to live, then causes you to die; then He will assemble you for the Day of Resurrection, about which there is no doubt,” but most of the people do not know. (Quran, 45:24-26)
I realized that people died more than they lived. The time spent living in the world commonly less than 100 years. Only those who were the lucky ones might lived few years more.
As a person who is still living, I keep reminding myself that a preparation for the day of Judgement is crucially important. I may not know how short my life is and I understand that this is a secret of Allah.
God is the Knower of the future; He does not permit anyone to unveil such knowledge. Only through the messenger that He chooses does He reveal future and past events (Quran, 72:27)
Keep doing good deeds and improving myself to follow Islamic rules to be a better living human as for now and later. InsyaAllah.