And Jesus cried out with a loud voice, and breathed His last. Then the veil of the temple was torn in two from top to bottom. (Mark 15:37–38)
What is the Significance of the torn curtain?
The veil or curtain separated the Holy Place from the Most Holy Place, the earthly dwelling place of God's Presence. (Hebrews 9:1-9). This signified that man was separated from God by sin (Isaiah 59:1-2). Only the High Priest could enter the Most Holy Place and then only once a year. However, when Christ died the barrier was removed allowing us direct access to God.
Therefore, brothers, since we have confidence to enter the Most Holy Place by the blood of Jesus, by a new and living way opened for us through the curtain, that is, His body, and since we have a great priest over the house of God, let us draw near to God with a sincere heart in full assurance of faith, having our hearts sprinkled to cleanse us from a guilty conscience and having our bodies washed with pure water. Hebrews 10:19-22
The tearing of the veil at the moment of Jesus' death dramatically symbolized that His sacrifice, the shedding of His own blood, was a sufficient atonement for sins. It signified that now the way into the Most Holy Place was open for all people, for all time, both Jew and Gentile.
When Jesus died, the veil was torn, and God moved out of that place never again to dwell in a temple made with hands (Acts 17:24). God was through with that temple and its religious system.
The veil was symbolic of Christ Himself as the only way to the Father (John 14:6). This is indicated by the fact that the high priest had to enter the Holy of Holies through the veil.
Notice also that the curtain/veil was torn from the top down. Solomon's temple was 30 cubits high (1 Kings 6:2), but Herod had increased the height to 40 cubits, according to the writings of Josephus, a first century Jewish historian. There is uncertainty as to the exact measurement of a cubit, but it is safe to assume that this veil was somewhere near 60 feet high. Tearing this veil from the top down signified that this was done through God's power.
References:
https://answersingenesis.org/contradictions-in-the-bible/when-was-the-temple-veil-torn-in-two/
https://www.gotquestions.org/temple-veil-torn.html