Mark 13:1,2 And as he went out of the temple, one of his disciples saith unto him, Master, see what manner of stones and what buildings are here! 2 And Jesus answering said unto him, Seest thou these great buildings? there shall not be left one stone upon another, that shall not be thrown down.
The disciples were awed by the amazing size and architecture of Herod's temple. Jesus shows them the folly of being impressed by the works of man. When the Roman Legion took Jerusalem in AD70 they tore the temple apart stone by stone thus fulfilling the Lord's prediction.
I hope you have found this helpful.