Question:

Some say the world will not actually end. That the “end of the world” is actually metaphor for each individual’s death. Is this true according to the Church? If yes, does the Church teach of a period of time?

Answer:

To put it simply : No. We believe in an actual end of human history, and the perfection of creation; “A new heaven and a new earth” where righteousness dwells and where the Lord will reign and live among his people.

"But according to his promise we wait for new heavens and a new earth in which righteousness dwells. Therefore, beloved, since you wait for these, be zealous to be found by him without spot or blemish, and at peace" (2 Pet. 3:13).
He will come again in glory to judge the living and the dead and his kingdom will have no end.... I confess one Baptism for the forgiveness of sins and I look forward to the resurrection of the dead and the life of the world to come. Amen. (Nicene Creed)

The Catholic Church teaches that Christ will come to judge the earth and to bring peace to it. Those who have died shall rise again to take their bodies. We all shall repossess our bodies then, those who were already in heaven and hell shall come out, and those in the world shall be transformed. Each shall receive the reward due them; a share in the Glory of Christ for all who are just, and condemnation for all who rebel against Him. We call Mary the “Icon of our hope” since she now dwells with her Son in the state we hope to be at the end of the world; united with our glorified bodies with Christ the Lord.

The Christian Creed - the profession of our faith in God, the Father, the Son, and the Holy Spirit, and in God's creative, saving, and sanctifying action - culminates in the proclamation of the resurrection of the dead on the last day and in life everlasting. We firmly believe, and hence we hope that, just as Christ is truly risen from the dead and lives for ever, so after death the righteous will live for ever with the risen Christ and he will raise them up on the last day. Our resurrection, like his own, will be the work of the Most Holy Trinity:
If the Spirit of him who raised Jesus from the dead dwells in you, he who raised Christ Jesus from the dead will give life to your mortal bodies also through his Spirit who dwells in you.
The term "flesh" refers to man in his state of weakness and mortality.The "resurrection of the flesh" (the literal formulation of the Apostles' Creed) means not only that the immortal soul will live on after death, but that even our "mortal body" will come to life again.
Belief in the resurrection of the dead has been an essential element of the Christian faith from its beginnings. "The confidence of Christians is the resurrection of the dead; believing this we live."
How can some of you say that there is no resurrection of the dead? But if there is no resurrection of the dead, then Christ has not been raised; if Christ has not been raised, then our preaching is in vain and your faith is in vain. . . . But in fact Christ has been raised from the dead, the first fruits of those who have fallen asleep. CCC 988- 991

When?

To save you some time, No one knows, not even the Church. Sincerely, what the Church concerns herself with is not to discern times but to minister salvation to all men in keeping with the command of Christ. His it is to know when he’ll come (and He knows), but ours it is to keep watch for He “comes like a thief”. Let us live righteous lives and leave everything in the hands of God’s mercy.