The crucifixion of Christ. Calculating from 444 B.C. to A.D. 33, one arrives at 478 years rather than the 483 years required. When the two calendars are adjusted, and one must do so for accuracy, a difference of about eight years will be discovered. Daniel made other amazingly specific and accurate prophecies centuries before Jesus was born. Note that Bible prophecies differ from other predictions of the future like those from Jean Dixon and Nostradamus.
Bible prophecies are specific.
In ancient times, the Jews considered one a false prophet if he or she was ever wrong. And the Jews used to put false prophets to death. The very day, Israel became a nation and the day they controlled Jerusalem is predicted in Ezekiel for example. Alexander the Great is named before he was ever born in Daniel, etc. I would recommend one research this subject further if he or she is interested in the truth of this matter.