Luke 19:41-44.
When Jesus came near Jerusalem, he saw the city and wept for it. "If only you know things which belong to the peace today! but they are hidden from your eyes. Your enemy will come surrounding you, and defeat you and your children onto the ground. They will not leave one stone upon another. This is because you didn't know the time of God's visit".
In AD 70, Jerusalem fell by Romans, and what Jesus said here was fulfilled.