JERUSALEM (JTA) — Tens of thousands of pilgrims traveled to Meron in northern Israel to mark the start of Lag B’Omer.

Mount Meron is the burial place of grave of Jewish Kabbalist and mystic Rabbi Shimon Bar Yochai, a popular pilgrimage site for the holiday. The pilgrims began lighting bonfires after midnight on Saturday night, with hundreds of thousands of people expected over the course of Sunday and Sunday night. The event draws many haredi Orthodox Jews.

Lag B’Omer marks the 33^rd day of the counting of the days between the holidays of Passover and Shavuot and the end of a minor mourning period recognizing the death of thousands of the students of the sage Rabbi Akiva. Bar Yochai was a 2nd century disciple of Rabbi Akiva and was revered for his teachings on Kabbalah, or Jewish mysticism. Lag B’Omer also commemorates Bar Yochai’s death and the revelation of the Zohar, a spiritual text. The bonfires are meant to symbolize the light of those teachings.

While bonfires were lit in Meron on Saturday night, the annual tradition was delayed throughout Israel by one night to Sunday night by the Chief Rabbinate in order to prevent the desecration of Shabbat by police and other emergency services in preparation for the gatherings. School closings were changed from Sunday to Monday, as were other planned celebrations.