The crashes that changed Formula One

    (CNN)Though it has been a divisive addition to Formula One cars this season, the "halo" proved its worth on Sunday during a spectacular opening-corner crash at the Belgian Grand Prix.

    When Fernando Alonso's car was sent airborne after a shunt from Nico Hülkenberg, the halo on Charles Leclerc's cockpit deflected the impact of the Spaniard's McLaren.
    The titanium structure, built around the cockpit to protect drivers' heads, sustained severe damage and left many wondering how bad the outcome could have been had it not been there.
      Its addition to the sport, which was not without controversy, is just one of a multitude of changes introduced to F1 over the past decades to make the sport safer.
        And some of those changes have come as a result of tragic accidents on the track.