Chris Froome seized the yellow jersey of the Tour de France leader after another day of drama in Belgium.
The 2013 champion finished second on the brutal climb up the Mur de Huy as Spain's Joaquim Rodriguez won the third stage.
But that was enough to put the Team Sky rider into the leader's jersey by just one second from Germany's Tony Martin. Froome took time out of all of his major rivals who could not live with him on the steep slopes.
The race was halted around 35 miles from the finish following a huge crash involving about 20 riders. Race leader Fabian Cancellara somersaulted two-and-a-half times into a ditch after being involved in the incident.
The Swiss rider, looking heavily dazed in his yellow jersey, bravely got back on his bike as the main field were eventually told to stop.
Cancellara, 34, got to the finish of the 100-mile (159.9km) stage but was clearly in pain and lost his grip on the coveted jersey after just one day.
Tour director Christian Prudhomme had heated discussions with riders from the window of his car before halting the race. But it quickly emerged that the race had to be neutralised as all the medics were dealing with the injured and so could not cover the rest of the peloton.
The crash looked to have been caused by France's William Bonnet touching wheels with another rider. The shunt sent several thumping into a lamppost and left others with broken bones and race-suits ripped to shreds on the roadside.
Three riders were forced to abandon on the spot, but the Netherlands' Laurens ten Dam popped his dislocated shoulder back in and carried on.
Etixx QuickStep's team manager Patrick Lefevre was unhappy with the decision to stop the race despite the injuries. He tweeted: "To be clear I hate crashes but this is really a dangerous precedent."
The race finally restarted 15 minutes later but it was neutralised for the first climb of the day up the Côte de Bohissau.
Froome attacked on the brutal final climb up the Mur de Huy - whose gradient hits 25% at times and averages out at nine - in a bid to take the stage.
The Nairobi-born rider was overhauled by Katusha's Rodriguez to finish three seconds back but with time bonuses it gave him the lead he will have to defend on the cobbles on Tuesday.