Twenty years ago Sunday, a fire deep inside an Alpine tunnel killed 39 people and turned a motorcycle-riding security guard who worked there into a hero. In the chaos just after the blaze, local French and Italian newspapers reported that the biker had raced in and out of the burning tunnel, saving as many as 10 people before dying in one last rescue attempt.

It was some time before investigators released a final, accurate account of the disaster at the Mont Blanc Tunnel: The biker, who was known by his nickname, Spadino, an Italian riff on his skinny frame, had not saved anyone. But he died trying to do so, and local bikers still gather at the tunnel mouth once a year to honor him.

While the legend was exaggerated, the horror of the fire — and its impact on tunnel safety — cannot be overstated. The lessons of the tragedy have guided tunnel design and engineering ever since, including recent American projects like the Port of Miami Tunnel and Seattle’s new S.R. 99 Tunnel.