Great Tribulation
In the futurist view of Christian eschatology, the Tribulation is a relatively short period of time where anyone who chose not to follow God before the Rapture and was left behind (according to Pre-Tribulation doctrine, not Mid- or Post-Tribulation teaching) will experience worldwide hardships, disasters, famine, war, pain, and suffering, which will wipe out more than 75% of all life on the earth before the Second Coming takes place.
According to Dispensationalists who hold the futurist view, the Tribulation is thought to occur before the Second Coming of Jesus and during the End Times. Another version holds that it will last seven years in all, being the last of Daniel's prophecy of seventy weeks. This viewpoint was first made popular by John Nelson Darby in the 19th century and was recently popularized by Hal Lindsey in The Late Great Planet Earth. It is theorized that each week represents seven years, with the timetable beginning from Artaxerxes' order to rebuild the Temple in Jerusalem (the Second Temple). After seven plus 62 weeks, the prophecy says that the messiah will be "cut off", which is taken to correspond to the death of Christ. This is seen as creating a break of indeterminate length in the timeline, with one week remaining to be fulfilled.
This seven-year week may be further divided into two periods of 3.5 years each, from the two 3.5-year periods in Daniel's prophecy where the last seven years are divided into two 3.5-year periods, (Daniel 9:27) The time period for these beliefs is also based on other passages: in the book of Daniel, "time, times, and half a time", interpreted as "a year, two years, and half a year," and the Book of Revelation, "a thousand two hundred and threescore days" and "forty and two months" (the prophetic month averaging 30 days, hence 1260/30 = 42 months or 3.5 years). The 1290 days of Daniel 12:11, (rather than the 1260 days of Revelation 11:3), is thought to be the result of either a simple intercalary leap month adjustment, or due to further calculations related to the prophecy, or due to an intermediate stage of time that is to prepare the world for the beginning of the millennial reign.
Read more about this topic: Futurism (Christianity)