 Complete the following phrase:  In the 1994 San Marino Grand Prix, during Friday practice Rubens Barrichello was launched over a kerb and into the top of a tyre barrier at the Variante Bassa, knocking the Brazilian unconscious, though quick medical intervention saved his life. During Saturday qualifying Austrian Roland Ratzenberger crashed head-on into a wall at over 310 kmh at the Villeneuve corner after his Simtek lost the front wing, dying instantly from a basilar skull fracture. The tragedy continued the next day, when the three-time World Champion Ayrton Senna lost control of his car and crashed into the concrete wall at the Tamburello corner on Lap 7. 