According to premillennialism, this is a seven-year period that immediately precedes the return of Christ and the millennial kingdom of His rule which lasts for 1,000 years. It will be a time of great peace (the first 3 years) and great war (the second 3 years) when the Antichrist rules over many nations. At the midpoint of the tribulation (at the end of the first 3 years), the Antichrist will proclaim himself worthy of worship. Many will bow down and worship the Antichrist, and many will refuse. Those who refuse to worship the Antichrist will be killed. The second half of the tribulation is called the Great Tribulation. It will involve the whole world (Rev. 3:10). There will be catastrophes all over the world. (See Matt. 24, Mark 13, Luke 17).