Sifting through the moments that turn a sport around, the episodes that not only define a time but resonate to affect the whole conduct of the game, is an almost futile endeavour or at least one bound to spark endless, unwinnable arguments.
In Formula One cases can be made for any number of moments. From Juan Manuel Fangio driving his Maserati to an unequalled fifth championship in 1957 to Jack Brabham's 1959 win in the rear-engined Cooper. Colin Chapman's unequalled contributions to the sport through the development of the Cosworth DFV-powered Lotus 49 and the introduction of the team's famous ground effect cars of the 70s all are worthy of vociferous championing.
But if you are to pinpoint an event that has truly altered the sport, the repercussions of which are still echoing through its consciousness and its public perception, then it is not a moment of triumph but one of appalling tragedy - the death of Ayrton Senna.
By the time the Formula One circus rolled into Imola for the San Marino Grand Prix of 1994, Senna had already achieved legendary status. The 34-year-old Brazilian had won three world titles in four years and was already spoken about in tones of hushed reverence as the successor to Fangio, the rightful heir to the title of greatest driver ever.
But that year Senna was in trouble. Despite claiming pole in the first two grands prix of the season, he lost the races to the young newcomer Michael Schumacher, whose Benetton was, he was sure, running with illegal traction control. He was also battling a problematic car, the Williams FW16.
The team lured him away from McLaren with the promise of unrivalled machinery but they failed to deliver - the FW16 suffered from aerodynamic problems that had caused Senna to complain about its nervousness.
But arriving at Imola the Brazilian was determined to beat Schumacher. It was not to be. The bad omens began on the first practice day when compatriot and friend Rubens Barrichello was hospitalised after a violent accident at the Variante Bassa. If that rattled Senna, worse was to come.
On Saturday, the young Roland Ratzenberger lost control of his Simtek on the approach to the Tosa turn and smashed into the wall. It was the first fatality in Formula One since Ricardo Paletti perished at the Canadian Grand Prix in 1982. It shocked a sport that had become complacent in regard to driver safety. Senna was distraught. Against the wishes of organisers he visited the scene of Ratzenberger's crash and returned visibly moved. His close friend and the sport's medical adviser, Professor Sid Watkins, feeling that the Williams driver was not in a fit mental state to race, advised Senna to withdraw. The triple world champion said he couldn't, there was too much expectation, too much to lose.
The following day Senna wept openly at the drivers' briefing as a minute's silence was observed for Rathzenberger but he still took his place on the starting grid. The Williams driver's fragile state of mind could not have been helped by a start-line shunt in which Pedro Lamy's Lotus slammed into the rear of J J Lehto's Benetton forcing the lead drivers to race behind the safety car. When the pace car left the track four laps later Senna screamed away with Schumacher in pursuit.
However, just one lap on, as the pair made for the flat-out Tamburello curve Senna's car suddenly stepped wide. The Brazilian fought for control but, barrelling through the turn at over 190 mph, even the great Senna couldn't react swiftly enough. The nose of the Williams slammed into the wall and, under the force of the impact, the right front wheel slammed back and a suspension arm pierced his helmet, causing fatal injuries.
While the racing world had been shocked by the death of Ratzenberger, it's doubtful that any great steps would have been taken to remedy the sport's safety problems based solely on the death of the Austrian. It took the death of its finest driver to push the Federation International d'Automobile, the sport's governing body, into a re-evaluation that continues still.
By 1995, despite worries over hasty implementation, the FIA rushed through new regulations governing driver safety, raising the height of the cockpit sides. The rules were strengthened the following year, adding high-density, impact-absorbant foam padding to cushion the driver's head in the event of a crash. Since then refinement upon refinement has been added.
While Senna's statistical legacy remains the three titles he earned at McLaren between 1988 and 1991, his incredible 65 pole positions, his 41 wins and his status as the second most successful driver of all time, his more profound bequest may be in the lives he has helped save. Just two years after the tragedy at Imola, Jos Verstappen lost control of his Arrows at the Belgian Grand Prix, his car sluing off track and impacting with a force of more than 40G. Thanks to the new, stronger cockpit sides he survived.
Jacques Villenueve lost control exiting the notorious Eau Rouge corner at Spa Francorchamps this year, his BAR pin-wheeling through a series of horrific rolls before bouncing to a halt. But for the strengthened cockpit the Canadian would surely have lost his life.
Formula One has been built on any number of thrilling, edge-of-the-seat moments of spectacular bravery and skill. One only has to point to the stupendous finish of the 1971 Italian Grand Prix in which just 0.61 seconds separated the top three to remember why motor racing exerts such a pull on the public imagination. But when countered against the statistic of a five-year period of no fatalities and only a handful of serious injuries, it is undoubtedly the events of May 1st, 1994, that have had the most profound effect on Formula One.
Perhaps without that tragic loss, the prospect of Formula One teams gathering in Melbourne in March to begin a new millennium of championships may never have come to pass.
