Lag B'Omer is also the anniversary of the death of Rabbi Shimon Bar Yochai, author of the first Kabbalistic work, the Zohar. When the ARI, the great Kabbalist of the 16th century, came to Tzfat, one of the customs that he instituted was that of visiting the tomb of Rabbi Shimon Bar Yochai on Mt. Meron on Lag B'Omer. In the 19th century, a new tradition was added -- taking a Torah scroll from the home of the Abu family in Tzfat and walking it to Mt. Meron.
Today, the Abu Torah scroll is ceremoniously taken to the Central Bus Station of Tzfat and driven to Meron, and with that the festivities of Lag B'Omer begin.