Answer, Part I: Discussions about the end times can get fairly complex, depending on how deep you want to go with it and what various aspects you wish to focus on. Here I am only going to give a very cursory view based around what most people care about: the chronology of events leading up to, during, and after Christ's second coming. The Scripture most often focused on is in Revelation 20:1–3, 7–8:
Then I saw an angel coming down from heaven, holding in his hand the key of the bottomless pit and a great chain. And he seized the dragon, that ancient serpent, who is the Devil and Satan, and bound him for a thousand years, and threw him into the pit, and shut it and sealed it over him, that he should deceive the nations no more, till the thousand years were ended. After that he must be loosed for a little while. . . . And when the thousand years are ended, Satan will be loosed from his prison and will come out to deceive the nations which are at the four corners of the earth.
In end-times discussions the thousand years are referred to as "the millennium" and most theories revolve around this period of time. Thus generally there are three schools of thought: postmillennialism, premillennialism, and amillennialism.
Postmillennialism teaches that society is generally improving and that for the millennium (usually taken to be a figurative length of time) before Christ's second coming the world will experience the reign of Christianity. In essence God's law will be civil law and all will live in peace, prosperity, etc. At the millennium's end a great apostasy will occur, Christ will return, the dead will be resurrected, and the final judgment will be concluded. While postmillenialism was popular among Protestant Christians during the 19th century, today its teaching is limited mostly to certain Calvinist sects.
Premillennialism is the most prevalent end-time theory among Evangelical and Fundamentalist Protestants. The popular Left Behind books are based on this view. Premillenialists believe that for 1,000 years (usually viewed literally) the world will see a "Golden Age" of thorough Christianization, just as Postmillennialists do. However they believe this millennium will occur after Christ's Second Coming, and as such He will reign physically on earth during this time. The final judgment occurs only after Christ's literal thousand-year reign on earth has been completed.
Within premillennialism there exists a doctrine called "the Rapture." The Rapture is theorized to be an event where believers in Christ, both among the dead and living, are secretly "snatched up" and taken from the earth to be with God in their glorified form. Those who believe this say that literally these people will simply disappear from the face of the earth, without a moment's notice. This view is based on an interpretation of 1 Thessalonians 4:16–17.Amillennialism sees the Revelation passage quoted in the beginning as symbolic. The millennium is not viewed as some sort of "Christian utopia" on earth with a set period of years, but simply the present time between Christ's death and His eventual return, where both good and evil co-exist and Christ reigns through His Church. Most amillennialists reject any teaching on there being a Rapture (at least the premillennial definition of it). Amillennialism has been the dominant belief regarding the end of times for most of the history of Christianity: while the earliest Christians postulated different theories, by the time of Augustine in the 4th century amillennialism had become the dominant view. This continued through the Protestant Reformation and as such most "mainline" Protestants such as Lutherans, Anglicans, Reformed, etc. still consider themselves amillennialists.
Among those who believe in the Rapture, there are, again, three different schools of thought: pre-tribulation (pre-trib), mid-tribulation (mid-trib), and post-tribulation (post-trib).
Like most Christians, premillennialists believe a time of tremendous hardship and persecution will afflict mankind before Christ returns -- this is called "the tribulation." Pre-trib folks believe the Rapture will occur before the tribulation and thus Christians will be spared this time of difficulty. This view was essentially first widely postulated and taught by a man named John Nelson Darby in the 1800s.
Mid-trib folks of course believe the Rapture will occur during the middle of the tribulation, and post-tribs believe the Rapture will occur at the end. A small few actually ascribe to none of these views but believe that several "mini-Raptures" will occur throughout the time leading up to Christ's return.
Part II: What is the Catholic belief regarding the end times?
The Catholic Church has historically been amillennial in nature, largely accepting Augustine's writings on the subject. That said, the Catholic Church has never made any official proclamation regarding what definitively is "the millennium." In actuality the Church has quite little to formally say about the end of times (which is somewhat surprising to some people, especially our Protestant brethren for whom the subject can be quite prominent in defining their faith).
The Catholic Catechism provides a general order of events which are believed to happen [CCC 673-677]. Chronologically they are:
1. the full number of the Gentiles come into the Church
2. the "full inclusion of the Jews in the Messiah's salvation, in the wake of the full number of the Gentiles" (the role of the Jews here is based off the Church's understanding of Romans 9-11)
3. a final trial of the Church "in the form of a religious deception offering men an apparent solution to their problems at the price of apostasy from the truth." The supreme deception is that of the Antichrist.
4. Christ's victory over this final unleashing of evil through a cosmic upheaval of this passing world and issuing the Last Judgment.
Catholics do believe in a "rapture" in that all those believers in Christ will eventually be gathered together, but not in the premillennialist sense that we will be secretly swept off the earth before, during, or after the time of tribulation. The most accepted interpretation is that this gathering together will happen after the return of Christ and as a part of the general resurrection of the dead, where after the Last Judgment all believers will go to be with God forever.
Apart from this, all specific Catholic end time theories are conjecture. They cannot be considered official stances of the Church, but if they fall within the general boundaries I've already explained, they aren't rejected either.
Some people like to get very detailed about the time frame and makeup of the Last Days. Throughout the history of the Church many saints have issued their own personal take, and even some Church-approved apparitions of Jesus and Mary (which Catholics aren't bound to believe but the Church has declared they are worthy of belief if one so chooses) have spoken with more specificity on the subject.
For a very specific timeline on the Last Days from a Catholic perspective, feel free to look at the following website (but remember, this is just one man's interpretation and is not official teaching): Catholic Prophecy by the blogger Catholic Knight.
For more explanation on the Catholic beliefs re: the end times, here are some helpful websites:
- Official teaching from the Catholic Catechism
- Are we living in the Last Days?
- In depth look at the Left Behind series, premillennialism, and the Catholic perspective
End of the Present World and the Mysteries of the Future Life by Fr. Charles Arminjon
Will Catholics Be Left Behind: A Critique of the Rapture and Today's Prophecy Preachers by Carl Olson
Trial, Tribulation & Triumph: Before, During, and After Antichrist by Desmond Birch
Ultimately regarding the time of Christ's return, we must remember Jesus' own words as recorded in Matthew 24:36, "But of that day and hour no one knoweth, not the angels of heaven, but the Father alone." Therefore, "be zealous to be found by him without spot or blemish, and at peace." (2 Peter 3:14)
The information provided here is, to the best of my ability and knowledge, in accordance with official Catholic teaching. I submit all things said here to the authority of the Catholic Church.