There are three popular views when speaking about the millennium (thousand years).
1. Premillennial View (Held by most non-denominational Christians). They see this chapter (Revelation 20) as a literal one thousand year reign of Christ on earth after his second coming and before the end of time. He will come when it becomes so bad and he will reign with a thousand years of peace.
2. Postmillennial View (Held by Reformed Protestants) understand the 1000 years as either a figurative or literal period of time prior to the second coming of Jesus Christ. This view holds that many will accept the Gospel and live in peace.
3. Amillennial View (Held by Catholics, Lutherans & Episcopalians and Methodists). The word speaks of "no literal millennium." This view was first held by St. Augustine in his book The City of God. The 1000 years symbolize the time that began when Jesus Christ established his Church, and now the Church is reigning with him until the consummation of time. According to Augustine, the first time Jesus came was the beginning of the initial stage of the kingdom. He defeated the devil and restricted his powers on the earth. The final stage of the kingdom will be fully established at the second coming of Jesus Christ at the end of time. This is when the enemy will be thrown into the lake of fire forever.