The ceremony of the priestly blessing at the Kotel has been practiced since 5731 (1970) and takes place twice a year – on the holiday of Sukkot and Passover. To catch the actual blessing you may need to fast-forward quite a bit, toward the end of the cantor’s repeat of the Amida prayer.
The source of the priestly blessing is in Deuteronomy 30:27: “The Levite priests rose and blessed the people, and their voice was heard, and their prayer went up to His holy abode, to heaven.”
Sefer Haroke’ach by Rabbi Eleazar of Worms (1176-1238) states that “If three hundred Cohanim were standing on the Mount of Olives and they would say the priestly blessing, the Messiah would come.” But since Cohanim are not allowed to ascend the Mount of Olives, which is a cemetery nowadays, the ceremony was moved to the Kotel.
So, all things considered, we could be watching the arrival of our redeemer, God willing, right on YouTube.