Families and friends of the 520 people who died in the 1985 Japan Airlines jumbo jet crash in Gunma Prefecture climbed to the mountainous accident site Sunday to mark the 27th anniversary of the worst single-aircraft accident in aviation history.

In an annual tradition, the visitors to Osutaka Ridge placed flowers and other offerings at the grave markers of the deceased.

Some climbed further toward the summit, gathered in front of a monument dedicated to the victims and offered a silent prayer, renewing their wish for airline and vehicle safety following a string of major traffic accidents, including a tour bus that crashed edge-on into an expressway sound barrier in the prefecture, killing seven people and injuring several others in April.

JAL President Yoshiharu Ueki will climb the mountain in the afternoon to pray for the victims.

The accident killed all but four of the 524 passengers and crew members aboard the Boeing 747, which was en route from Tokyo to Osaka.