One moment, the afternoon sky was clear. The next, it was echoing with the crack and thunder of exploding fireworks, filled with multicolored smoke.
The apocalyptic scene tearing through the fireworks market in the Mexico City suburb of Tultepec struck terror into witnesses' hearts.
"The earth moved," said Angelica Coss, a 25-year-old resident who lives just streets away from the market. "It felt like a plane had crashed, like bombs were being dropped." "I went up to the roof of my place and others were already there and we saw the market was blowing up. And all the smoke started to cover us," she told AFP.
Inside the San Pablito market itself - Mexico's biggest with 300 stands selling tons of pyrotechnics - horror was unfolding.
"You just heard the blast. And everything started to be on fire. People came running out on fire," Walter Garduno said.
"People were alight - children," he added before trailing off.
Pops and thuds of multiple fireworks went off, sending flaming rockets into a busy crowd that had been shopping for Christmas and New Year's festivities.
The devastation reduced the market to a smoldering wasteland of ash, charred metal and concrete.
It was another cruel blow to San Pablito, which had already suffered runaway conflagrations in 2005 and 2006.
Its vendors - who operated with licenses issued by the defense ministry - had boasted theirs was Latin America's safest fireworks fair.
But that claim was proven wrong when fireworks somewhere in the market ignited, setting off the catastrophic chain reaction that consumed the place within minutes.
First responders were initially stymied by the continuous blasts going off in different parts of the market, spread over four hectares (10 acres) next to a traffic intersection.
The smoke choked them as they pulled out dozens of wounded people, most of them suffering burns.
One of the first to dive into the disaster zone was Victor Hugo Samantes, whose relatives worked in some of the market stalls. They all managed to escape.
"It's incredible because you're used to seeing everything happening, people working, manning their stalls," he said, a mask covering his mouth. "And now, to see it like this..." The blackened expanse that used to be the San Pablito market now contained hundreds of police and emergency workers.
The authorities have started an investigation.