((This story corrects day in second paragraph))

NICE, France - (Reuters) - A child's doll lying in the street stares up into the night sky next to a dead body covered in a metallic blanket - an image that has come to symbolize the Bastille Day massacre when 84 people were killed by a truck plowing into holidaying crowds.

But the photographer, who rushed out of his Nice apartment in the confusion and fear of Thursday night, had not even seen the doll when he set to work shooting pictures on the Promenade des Anglais, and like everyone there, still had no real idea of what had happened.

"I couldn’t get through on my motorbike and, as I parked, there was a body next to my bike. It was when I looked into my rearview mirror that I saw all the other bodies just behind me," veteran Reuters photographer Eric Gaillard said.

Around a dozen bodies, some already covered with tablecloths taken from nearby restaurants, lay on what is one of France's best known seaside roads. Police and soldiers - many pointing their guns - were still in a state of confusion.

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"The conditions were very difficult, it was dark, police trying to stop us work ... and with some people there who wanted to hit me, who threw stones. I understand. The situation was very chaotic," Gaillard said.

He was not supposed to be working that night, taking time off after covering the Euro 2016 soccer championship. Around 9 p.m. his wife suggested they pop outside to see the annual fireworks, but he persuaded her to stay in watching TV.

When a colleague called from Paris to say a truck had hit people in central Nice, he assumed it was a traffic accident - not something his international news agency would normally cover.

"Suddenly I received an alert on my phone, the local authority announcing there had been an attack. I didn't stop to wonder what it was, I grabbed my camera and set out on my motorbike."

Gaillard, 58, has seen plenty of death and destruction in his 31 years with Reuters, but he never expected to see a war zone outside his flat on the Cote d'Azur.

"When you go to a war you know it's a hostile environment, you expect to see some unpleasant things ... (but) I was very shaken by what I saw that night because it's my city, Nice, 500 meters from my home, in a holiday setting."

The doll photo has gone viral on the internet, and often been captioned to say it shows a dead child beneath the foil emergency blanket, but in fact nobody knows for sure the age of the victim.

"Given its size, I don’t think it was a child. I don’t know why the doll is there," Gaillard said. "Was it a parent who was with a child – hence the doll? Did someone put the doll there at some point, for some unknown reason? Everyone is asking me."

Gaillard agrees that of all the photos he took that night, this one is the most poignant. But shots that show victims lying under the palm trees next to the beach convey the shocking scene of mass murder in a peaceful holiday town.

"It's people who are strolling, people jogging, people in their swimming costumes. And here they are ... the wider angle views with bodies left and right are also very symbolic of that evening."

(Writing by Robin Pomeroy, editing by Mark Heinrich)