Some 20 riders were involved in a massive crash at Stage 3 of the Tour de France in Belgium on Monday, causing organizers to temporarily halt the race.
Video shows the cyclists on a flat, straight and slightly downhill part of the road, traveling at high speeds with just under 37 miles of the stage remaining, reports Yahoo News.
Just as cyclists were beginning to make a move to the front of the pack, one rider clips the wheel of the cyclist in front, who goes down suddenly. At speeds of around 50 m.p.h., there was no time for those behind to react, and so the riders crashed into one another, resulting in a massive pileup of wheels, frames and spokes.
In all, six riders were forced to pull out of the race.
Competitors began the Tour de France 2015 in Utrecht, the Netherlands, on July 4 and will ride around 2,000 miles (3,360 km) over 21 stages until they finish in Paris on July 26.