The people who see all the events described by Jesus in Matthew 24, Mark 13 and Luke 21 come to pass will be the terminal generation. The people alive shortly before the second advent. The tribulation is included in these events. Since we do not know when the tribulation will begin we cannot know the terminal generation. However, when the tribulation does begin the saints will have a better idea of the time of the second advent. There yet must be a third temple with the prescribed sacrifices being performed, a false prophet calling fire down from heaven to burn up the sacrifices, a man claiming to be God who will end those sacrifices and a mark of 666 forced on the people or gladly accepted by the people. A great deception on the Earth with great loss of life accompanied by the wrath of God. We are just not there yet but I think we are getting close. Israel is trying to become a monarchy and build the third temple, the seventh king, the U.S. , is near to falling, it is as it was in the days of Noah and deception is growing. If you are alive when the antichrist arrives then you will be in the terminal generation.