The death of Ayrton Senna 25 years ago changed Formula 1's attitude to safety to such an extent that only one driver, Jules Bianchi in 2014, has since suffered a fatal accident.
In 1994, F1 had gone eight years without a death.
After 10 drivers died in the 1970s, only four were killed in the 1980s, the last was Elio de Angelis in 1986.
Then came the black weekend at Imola at the start of May 1994 when Roland Ratzenberger died in qualifying on the Saturday and Senna in the race on the Sunday.
Those deaths rocked the drivers and the international motorsports federation (FIA).
Senna's former teammate Gerhard Berger, told AFP: "We got too confident that the dangerous times were over. We realised that it had not changed at all and that we had got lucky for a while. That shook the FIA, the teams, the drivers. After this, everybody joined forces together with the FIA in the lead and it came to a very good result."
An Italian court eventually blamed a break in a hastily adapted steering column on Senna's Williams car for the crash.
"Regardless of whether that steering column caused the accident or not, there is no escaping the fact that it was a bad piece of design that should never have been allowed to get on the car," said Adrian Newey, who helped design the car and is considered the best F1 engineer, wrote in his autobiography in 2017.
He also wrote that the crash was linked to the instability of the Williams.
After the car hit a concrete wall on the Tamburello corner at more than 200 km/h, the right front wheel and suspension were hurled into the cockpit.
A piece of metal hit Senna's head and killed him.
In the following days, drivers, including Michael Schumacher, Niki Lauda and Berger, reformed the Grand Prix Drivers' Association and called for a reduction in speed, which was introduced for the Spanish Grand Prix at the end of May.
By Canada in mid-June, the cockpit had been lengthened and reinforced and the suspension strengthened.
The next season, 1995, brought higher norms for crash tests.
In 1996, the protection round the driver's head was reinforced. In 1998, the wheels were attached to the car by tethers to stop them flying off.
A head and neck support system (HANS), which attached the helmet to the shoulders and is designed to protect the spine, was introduced in 2003.
It was followed last season by the halo to protect a driver's head.
Senna's crash also changed attitudes to track layout.
F1 continued to race at Imola until 2006, but the Tamburello was remodelled in 1995 to become a chicane.
More than a third of the courses on this year's F1 calendar are "Tilkedromes", tracks designed, or renovated since 1995 by the German engineer Hermann Tilke.
They are wider, have bigger run off areas on the curves and move the fans further away.
Senna's death also altered the attitude of the public.
"The biggest difference between the death of Jim Clark on the 7th of April 1968 and Ayrton Senna on the 1st of May 1994 is that the world needed to know the answers as to why it had happened, why is this man dead, why is motor racing so dangerous?" Maurice Hamilton, the long-time Observer motorsports correspondent said in '1: Life on the Limit' a 2013 documentary on the history of safety in the sport.
"The death of Ayrton Senna was relayed by television in the living rooms of million of people around the world, to people who didn't really know about motor racing but knew of him. Somebody had to be blamed."