If you want to watch what happened then see the video below.
If you do keep your eyes on the left of the screen just as they are getting to the finish line.
When it shows it again from above look at where the lead cyclist (who caused the crash) starts off - in the middle of the road - and look where he ends up - up against the railings.
He clearly tried to close the door on the bloke in second and over did it - look at his shoulder and elbow!
The bloke was disqualified obviously and the man who crashed also took out an official stood behind the barriers as well.
The latest report is that cyclist has suffered a brain injury and has been put in an induced coma, and the official suffered spinal injuries, so unfortunately very serious stuff.