#1 Mark Webber and Fernando Alonso, 2003

The 2003 Brazilian Grand Prix was one of the most action-packed F1 races of all-time, with the Safety Car leading the most laps that day. The race seemed to be settling down after 54 laps, but Mark Webber lost the back end of his Jaguar going up Juncao, a real challenge in the wet like on that day.
The Aussie slammed into barriers on the outside of the corner, destroying the left side of his car, before pirouetting across the track and settling on the other side of the road. Webber was fine, but his crash had left a lot of debris on the circuit, something that would soon cause disaster.
Fernando Alonso hadn't heard the news of Webber's incident and slammed into one of the stray tyres in the middle of the track at full speed, around 180mph. The crash detonated Alonso's front right suspension, sending him into the tyre barriers on the inside, before spinning violently across the track, in a mirror image of Webber's crash.
The impact winded Alonso, and he failed to take to the podium, as he had to receive treatment by the side of the track. A crazy end to a crazy race.