Bodies flew "like bowling pins" and people screamed in terror and fled in every direction as a killer truck ploughed through a crowd at Bastille Day celebrations in this French city, killing 84 people in an unprecedented terror attack.
Many who survived the horrific Thursday night carnage at Promenade des Anglais, the main street in Nice, recalled how the heavy duty white colour truck drove into unsuspecting men, women and children, crushing everyone.
In no time, joyous scenes turned into blood-curdling horror, French and other media reports quoted witnesses as saying.
Journalist Damien Allemand, like countless others, had just finished enjoying the fireworks and was watching kids throw rocks in the sea when, suddenly, everything went wrong.
When he heard the first screams from a distance, Allemand thought some fireworks may have gone out of control.
"A fraction of a second later, a huge white truck flew by at a crazy speed, driving over people, twisting the wheel to cut down the maximum number of people," he said, recalling those deathly moments.
"I saw bodies fly like bowling pins along its path. Heard noises, screaming that I will never forget. I was frozen with fear," he wrote in a post.
As people began to run in different directions, many not knowing why except that something was dangerously wrong, the frightened Allemand, like hundreds more, took refuge in one of the many roadside restaurants.
When he came out, he bumped into a friend, Raymond, around 50, who was in tears and who gasped: "There are dead bodies everywhere."
Indeed there were, every five meters, and limbs. And lots of blood.
Not satisfied with running over people, the killer driver -- identified as Mohamed Lahouaiej Bouhlel, a 31-year-old Frenchman of Tunisian origin -- opened fire at revellers before police shot him dead.
Dominique Molina was on a hotel balcony when she heard "banging sounds" the truck made as it ran over people. She heard shrieking and saw flocks of people run frantically among fallen bodies.
Her husband Tony said they saw at least 10 bodies strewn on the street. "These bodies kind of sat. It was sad, because there were families lying down, crying next to these bodies."
Maryam Violet was at a restaurant when a frightened mob ran into it to take shelter. Confused, she went out and couldn't believe her eyes.
"I saw ... a lot of single dead bodies with no one around them," she told CNN. There were also fallen bicycles, street lamps and debris everywhere.
There were disturbing videos of the crowd jumping into the sea to save their lives, BFMTV reported. Another video showed people screaming as well as running everywhere.
An American witness told journalists that he was standing 15 feet away as the truck drove into the crowd "mowing bodies over" and accelerating as it hit the victims.
Among the first to die was a middle-aged Muslim woman. Two of her sons and other family members stood around her body, weeping.
So numerous were the bodies that to protect their dignity, people covered some of them with tablecloths snatched from nearby restaurants.
It later transpired that the truck had come from a side street near a children's hospital, taken a left and mounted the sidewalk opposite a row of balconied seaside villas and apartment buildings.
Although it was night, the trucks's headlights were off. And there was no honking.
"Nobody in the way stood a chance," said one man, Pierre Roux.
The beach attendants were the first to reach the scene. They brought water for the wounded and towels to spread over the dead.
By the time police officers arrived, it was all over. All they could do, after killing the truck driver, was to direct the shell-shocked survivors where to go.