#1 - Lap 1 Melee, Belgium 1998
Nothing has matched this before or since this whole race was full of huge incidents but this was the largest of them all and the biggest in Formula 1 history. The Great Murray Walker described the crash as "the worst start to a Grand Prix" in the whole of his life, and it's hard to disagree with him.
Spa-Francorchamps weather is unique on the calendar (just look at the recent WEC race there) and it was typically wet in Belgium for the start of this one. Going out of La Source, Eddie Irvine and David Coulthard tangled (to this day, both blame the other for this accident and due to the spray, we can't see whose fault it was).
Regardless of where the blame lay, Coulthard spread into the wall, blocking the track and because of the fog-like spray, collected most of the field on the run down to Eau Rouge. Car after car slammed into the growing wad of carbon fibre traversing down the track, 13 in total were damaged beyond repair.
Only four drivers didn't restart, but this was in the days of the "T-car", a spare car to be used in case of a restart, so nine other drivers restarted thanks to this rule. It was a race of huge attrition, only eight making the chequered flag.
Needless to say, the race was red flagged and restarted later, after the large cleanup operation had been completed.
Which was the biggest F1 wreck ever in your view? Was it Belgium '98 or another pile-up? Let us know in the comments below!