This chapter is often called the "little Apocalypse" in Matthew. The tricky part is that Jesus appears to be talking about two separate events. One in the near future. The other one is in the distant future. The near future prediction has to do with the destruction of Jerusalem and its Temple. This prediction begins with 24:1-2. Jesus then shifts to a discussion of the "end of the age" (24:3-8) which speaks of signs in the heavens, wars and rumors of wars and proceeds to speak of persecutions that will be a portend of the end. We then shift back to the destruction of Jerusalem (15-28). Here Jesus is describing the destruction of Jerusalem that happened in AD70. Galilean rebels revolted against Roman Rule in AD67 and actually took and held the city of Jerusalem and the fortresses at the Herodion and Masada. Rome sent General Titus to "pacify" the region and Titus and his army leveled the city of Jerusalem in AD 70 and proceeded to do the same to the Herodian and Masada by AD 73.
Verse 29 returns to the "end of the age" conversation with apocalyptic signs and wonders in the heaves and in the earth and the coming of the Son of Man in power with the sound of the trumpet. The chapter ends with some more general lessons about paying attention to what is going on around us (spiritually and culturally speaking) and the need to be on our guard. Verse 45 begins a parable about the faithful and unfaithful servant. The faithful one does his master's bidding and is ready when he returns. The unfaithful assume that when the master is delayed he is not coming and proceed to behave as if they were actually in charge. The end result is that wonderful biblical phrase: "weeping and gnashing of teeth (51)."