The Storm Before Dawn
The few years just prior to the return of Jesus Christ (see When Will Christ Return? and Where Will Christ Return?) will be a time unique in all of human history, not necessarily the events themselves, but the intensity (see Never Before, Never Again). War will be so rampant that, unless it (and all of The Lord's wrath because of it i.e. see War With The Lamb) were not stopped, no humans would survive - so it will be stopped, as Christ the Conqueror For Peace himself prophesied:
"13:8 For nation shall rise against nation, and kingdom against kingdom: and there shall be earthquakes in divers places, and there shall be famines and troubles ... 13:19 For in those days shall be affliction, such as was not from the beginning of the creation which God created unto this time, neither shall be. 13:20 And except that the Lord had shortened those days, no flesh should be saved: but for the elect's sake, whom he hath chosen, he hath shortened the days" (Mark 13:8,19-20 KJV).
"They shall look upon me whom they have pierced"
The "Old Testament" prophet Zechariah (most of his prophecies are in fact beyond even "New Testament" because the events that he foresaw are yet in the future) was given to describe the events leading up to the return of the Messiah, including how Jerusalem will become the focus of a religious frenzy by people ("Christian" and Jewish) who claim to obey God while blatantly disobeying Him (see the Fact Finder question below).
"12:1 The burden [see Oracles] of the word of the LORD for Israel, saith the LORD, which stretcheth forth the heavens, and layeth the foundation of the earth [see The Lord's Plumb Line], and formeth the spirit of man within him. 12:2 Behold, I will make Jerusalem a cup of trembling unto all the people round about, when they shall be in the siege both against Judah and against Jerusalem.
Zechariah's writings are filled with amazingly specific and detailed Messianic prophecies that link past and yet-future e.g. "they shall look upon me whom they have pierced" in the verses below was written before Christ's crucifixion, and yet it includes the time after His return. The Book of Revelation reiterates the same prophecy: "1:7 Behold, he cometh with clouds [see The Clouds of Heaven]; and every eye shall see him, and they also which pierced him: and all kindreds of the earth shall wail because of him" (Revelation 1:7 KJV).
12:10 And I will pour upon the house of David, and upon the inhabitants of Jerusalem, the spirit of grace and of supplications: and they shall look upon me whom they have pierced, and they shall mourn for him, as one mourneth for his only son, and shall be in bitterness for him, as one that is in bitterness for his firstborn.
Fact Finder: Where is the "abomination of desolation" going to happen? What is Christ going to do about it?