And going out, YHWSO went away from the Set-apart Place, and His taught ones came near to point out to Him the buildings of the Set-apart Place. And YHWSO said to them, “Do you not see all these? Truly, I say to you, not one stone shall be left here upon another, at all, which shall not be thrown down.” And as He sat on the Mount of Olives, the taught ones came to Him separately, saying, “Say to us, when shall this be, and what is the sign of Your coming, and of the end of the age?”
TS2009 - Matthew 24:1-3

In a literal sense the Son of God talks about the destruction of the physical temple in Jerusalem. But in a spiritual sense He talks about His Body (John 2:21). The Son of God is the stone that the builders, the Jewish authorities, rejected (Matthew 21:42, Psalms 118:22). His physical body was destroyed when the Jews and Romans killed Him. And after three days the Son of God was raised by God as a spirit. The rest of the New Testament clearly talks about the Body of the Messiah symbolizing the government of God's people who have to be gathered (Romans 12:4-5, 1 Corinthians 12:12-14, Colossians 1:18-24, etc). This work needs to be finished before the time of the end comes. From the viewpoint of the Old Testament people the First Coming of the Messiah might have been viewed as the sign of the end of that age. But history continued and Satan obviously still rules this world and we are getting closer to his Global Empire or world government. The disciples of the Messiah seem to know that the end of the age is about His Coming (in spiritual form) which happens somewhere in the future.

And YHWSO answering, said to them, “Take heed that no one leads you astray. “For many shall come in My Name, saying, ‘I am the Messiah,’ and they shall lead many astray.
TS2009 - Matthew 24:4-5

The Jews were expecting the Messiah in those days. Of course many Jews rejected the true Messiah. Therefore it is not surprising that at that time many false Messiahs arose (1 John 4:1, 2 Corinthians 11:13, Galatians 2:4, 2 Peter 2:1, Acts 13:6). But since the destruction of the temple in 70 AD many more false messiahs arose in the world under the power of Satan.

“And you shall begin to hear of fightings and reports of fightings. See that you are not troubled, for these have to take place, but the end is not yet. “For nation shall rise against nation, and reign against reign. And there shall be scarcities of food, and deadly diseases, and earthquakes in places. “And all these are the beginning of birth pains.
TS2009 - Matthew 24:6-8

In 66 AD the Jerusalem riots took place, massive unrest in the center of Roman Judea, which became the catalyst of the Great Revolt in Judea. In 66 AD the First Jewish–Roman War began. In 69 AD the Year of the Four Emperors took place. Scarcities of food took place (Acts 11:28, Josephus). Deadly diseases took place (Acts 28:9, malaria). Earthquakes took place (Acts 16:26). But wars and rumours of wars have been a constant reality in the history until now. Obviously much greater wars and disasters took place in the time since the destruction of the second temple in 70 AD.
More importantly, after the first literal temple on earth was completed God warns king Solomon, who built God's temple, that if the king would ever turn his back on God and worship other gods He would break the covenant that He made with king David, Solomon's father (2 Chronicles 7). We all know how the story of Solomon ended, after building the temple he started worshiping other gods because of his many foreign women. So obviously, God held His Word and broke the covenant. It is astonishing how many people, especially Christians, still believe there will be a literal temple on earth. The Messiah came to earth and brought God's renewed covenant which is about the spiritual New Jerusalem. It has nothing to do with the earthly Jerusalem.
Revelation 12 speaks of birth pains symbolizing the yearning of God's people for the Second Coming of the Son of God.

“Then they shall deliver you up to affliction and kill you, and you shall be hated by all nations for My Name’s sake. “And then many shall stumble, and they shall deliver up one another, and shall hate one another. “And many false prophets shall rise up and lead many astray. “And because of the increase in lawlessness, the love of many shall become cold. “But he who shall have endured to the end shall be saved. “And this Good News of the reign shall be proclaimed in all the world as a witness to all the nations, and then the end shall come.
TS2009 - Matthew 24:9-14

The phrase "all nations" can be interpreted in two ways. From the viewpoint of God's people at that time "all nations" could have meant all the world inhabited by the descendants of the twelve tribes of Israel who were scattered during history. From Jerusalem to Greece and Rome the disciples of the Son of God were persecuted, imprisoned and killed (Acts 7). But before the end shall come the Good News of the Kingdom of God will be proclaimed in all the world. Obviously the end has still not come, history is still in the making and Satan still rules. The Good News of the Kingdom of God still has to be proclaimed in all the world before Satan will be bound.

“So when you see the ‘abomination that lays waste,’ spoken of by Daniel the prophet, set up in the set-apart place” – he who reads, let him understand – “then let those who are in Yehudah flee to the mountains. “Let him who is on the house-top not come down to take whatever out of his house. “And let him who is in the field not turn back to get his garments. And woe to those who are pregnant and to those who are nursing children in those days!” “And pray that your flight does not take place in winter or on the Sabbath.
TS2009 - Matthew 24:15-20

See Daniel's vision of the Ram and Goat for the abomination that lays waste. It seems that this abomination is reflected in the image or statue of king Nebuchadnezzar's dream. In the time of the end the last little horn or king will force all people to worship that image of the beast. From the viewpoint of the people at the time of the Messiah it may seem like a direct and literal warning for those who lived in Jerusalem to flee to the surrounding mountains when Jerusalem would be surrounded by the Romans, as happened around 70 AD. But from the viewpoint of the people since that time it is a warning to flee to the spiritual mountain of God. In the Old Testament for example Zion and Jerusalem are likened to mountains of God (Psalms 2:6, Daniel 9:16). Most likely the Messiah points to the future New Jerusalem which will be set up in the time of the end when also Satan will be bound.

For then there shall be great distress, such as has not been since the beginning of the world until this time, no, nor ever shall be. “And if those days were not shortened, no flesh would be saved, but for the sake of the chosen ones those days shall be shortened.
TS2009 - Matthew 24:21-22

Before the Siege of Jerusalem in 70 AD there was a civil war between different Jewish factions. The Romans built a trench and a wall around Jerusalem. Everybody that tried to escape was crucified on top of the wall as an example for those inside. According to historicus Josephus more than 1 million people were killed because it happened to be the time of the festival of Passover. Those who managed to escape the city were persecuted by the Roman army and executed. The Romans killed the armed and elder people, 97,000 were enslaved, of which thousands were forced to become gladiators and eventually expired in the arena. This is how the Romans dealt with rebellious people. And it happened because those people did not heed the warning from the Messiah, Whom they rejected. Although this event is impressive this is not the worst kind of disaster that ever took place on earth. So obviously the phrase nor ever shall be points to a future event that will affect the whole world.

“If anyone then says to you, ‘Look, here is the Messiah!’ or ‘There!’ do not believe. “For false messiahs and false prophets shall arise, and they shall show great signs and wonders, so as to lead astray, if possible, even the chosen ones. “See, I have forewarned you. “So if they say to you, ‘Look, He is in the desert!’ do not go out; or ‘Look, He is in the inner rooms!’ do not believe.
TS2009 - Matthew 24:23-26

The great deception will reach its peak on earth. The Son of God forewarns that the Second Coming will not be like the First. The Son of God will spiritually return, not physically like the first time. His literal body was destroyed, but His spiritual Body was raised. What matters after the Messiah is not the literal physical temple, but the spiritual temple of the New Jerusalem.

For as the lightning comes from the east and shines to the west, so also shall the coming of the Son of Adam be.
TS2009 - Matthew 24:27

In a time of great spiritual darkness in this ever more Godless world ruled by Satan, the Son of God will shine His spiritual light of truth. See also Psalms 97.

For wherever the dead body is, there the vultures shall be gathered together.
TS2009 - Matthew 24:28

In Revelation 18:1-2 it is said that the destruction of Babylon the Great, who is likened to a whore, will leave behind a place for unclean spirits and unclean birds. Likely the vultures symbolize demons.

And immediately after the distress of those days the sun shall be darkened, and the moon shall not give its light, and the stars shall fall from the heaven, and the powers of the heavens shall be shaken.
TS2009 - Matthew 24:29

The stars shall fall from the heaven is an important given because it confirms that Satan and his fallen angels will be banned from heaven in the time of the end. This information is important for understanding the vision about The Woman and Dragon of Revelation 12. They will be thrown to earth after they loose the war with Michael and his army. Satan and his fallen angels will try everything to deceive as many people as possible in the short time they have left on earth. See also Revelation 6:12-14, Joel 2:10,31, Joel 3:15, Isaiah 13:10, Ezekiel 32:7.

“And then the sign of the Son of Adam shall appear in the heaven, and then all the tribes of the earth shall mourn, and they shall see the Son of Adam coming on the clouds of the heaven with power and much esteem. And He shall send His messengers with a great sound of a trumpet, and they shall gather together His chosen ones from the four winds, from one end of the heavens to the other.
TS2009 - Matthew 24:30-31

The messengers of the Son of God will gather the elect for the Kingdom of Heaven, the 144,000 (Revelation 7:1-4., 1 Corinthians 15:50-55, 1 Thessalonians 4:15-17).

“And learn this parable from the fig tree: When its branch has already become tender and puts forth leaves, you know that the summer is near. “So you also, when you see all these, know that He is near, at the doors.
TS2009 - Matthew 24:32-33

In Luke 13 we find the parable of the fig tree which is about a barren fig tree not producing fruit. It is about God's patience with His unfaithful people. In Matthew 21 the Son of God curses a fig tree which produces no fruit and it withers immediately. In regard to the literal Jerusalem it shows that the warnings will one day stop and righteous punishment will be executed. See also Seventy Weeks. In regard to the time of the end it will be a sign of the Second Coming to God's people.

“Truly, I say to you, this generation shall by no means pass away until all this takes place. “The heaven and the earth shall pass away, but My words shall by no means pass away.
TS2009 - Matthew 24:34-35

Speaking to His disciples this probably means that Jerusalem would be destroyed during their generation. Speaking to the world, which obviously continued on the same footing after Jerusalem's destruction, this probably means that all the things spoken of here, about the great tribulation and His Second Coming, will take place within the timespan of one generation, it won't take very long.

“But concerning that day and the hour no one knows, not even the messengers of the heavens, but My Father only.
TS2009 - Matthew 24:36

The Son of God will come like a thief in the night (Revelation 16:15, 1 Thessalonians 5:2-4, 2 Peter 3:10). Although we can see and interpret the signs of His Second Coming, and therefor we can know when the time is near, we cannot know the exact date or time. This means that all the people throughout history, especially those in Christianity, who attempted to calculate the year in which it would happen were simply false prophets who ignored the Word of God.