Twenty-One Special Judgments:

There are a total of twenty-one special judgments that fall upon earth during the Tribulation period. They are in three series of sevens described as seals, trumpets, and vials (or bowls):

The Seal Judgments:

This is the beginning of the program of God to pour out judgments upon the earth. I encourage you to open your Bible and read each judgment carefully to understand the finality of God's pronouncements. These include:

The world's greatest dictator (Revelation 6:1-2)
The world's greatest war (Revelation 6:3-4)
The world's greatest famine (Revelation 6:5-6)
The world's greatest death blow (Revelation 6:7-
The world's greatest persecution (Revelation 6:9-11)
The world's greatest ecological disaster (Revelation 6:12-17)
The world's greatest hour of fear ... actually the lull before the storm (Revelation 8:1)
The Trumpet Judgments:

The trumpets of heaven sound an alarm throughout the world announcing the public judgments of God. Each blast ushers in an added judgment.

The world's greatest fire (Revelation 8:7)
The world's greatest oceanic disturbance (Revelation 8:8-9)
The world's greatest pollution of water (Revelation 8:10-11)
The world's greatest darkness (Revelation 8:12-13)
The world's greatest pestilential invasion (Revelation 9:1-6)
The world's greatest army (Revelation 9:16)
The world's greatest storm (Revelation 11:15-19)
The Vial Judgments:

The world's greatest epidemic (Revelation 16:2)
The world's greatest contamination by blood (Revelation 16:3-7)
The world's greatest contamination by blood, continued (Revelation 16:3-7)
The world's greatest scorching (Revelation 16:8-9)
The world's greatest plague (Revelation 16:10-11)
The world's greatest invasion (Revelation 16:12)
The world's greatest earthquake (Revelation 16:18)
These twenty-one judgments unleash unbelievable war, ecological disasters, and atomic catastrophe on our earth. Note this judgment in particular; Revelation 14:20 reads, "And the winepress was trodden without the city, and blood came out of the winepress, even unto the horse bridles, by the space of a thousand and six hundred furlongs." According to today's calculations, that is a river of blood two hundred miles long-the exact length of the nation of Israel. Think of it! An entire nation saturated and soaked with blood. As believers, you and I can be grateful that the Rapture is coming, because it means we-the Church of Jesus Christ-will not be present to endure this terrible suffering. The Bride will be at home, at the marriage ceremony, and afterward return for the supper (Revelation 19:7-16).

http://www.jewishroots.net/library/end-times/twentyone_judgments.html