The massive earthquake rattled through Mexico City at about 1 p.m. local time Tuesday, razing buildings and rousing thick clouds of dust. As residents left their offices and homes, at least 44 of which sustained severe damage or collapsed entirely, the sun was glaring high in the sky.It was midday, and the children were still in school.Roughly 24 hours later, the quake-racked city is still digging through the rubble for signs of survivors — but one school in particular has drawn the desperate attentions of rescue workers. At Enrique Rebsamen, a school attended mostly by elementary-school age children, an entire wing of the three-story structure had fallen in the temblor."We ran outside because things started to fall," one neighbor told Imagen Noticias. "And once we ran out to the patio, to the street, we saw the cloud of dust."In a span of minutes, dozens of students and their teachers had been trapped or buried between pancaked sheets of concrete and stone. At least 21 children and four adults died. At least 30 other people remained missing as of early this morning.Hundreds more swarmed the rubble in the hours after the building's collapse: rescue workers, soldiers, parents and neighbors. They brought what they had at hand, makeshift instruments found at home and applied to the desperate task of digging for life."The houses are being lent as hospitals. We brought shovels, picks, materials for construction. And I'm still here," one volunteer told Imagen Noticias. "We brought shovels, spikes, first aid material.""They were small children. They were from kinder, from elementary school," she added, her voice breaking as she battled back tears. "I mean, children that couldn't defend themselves."It was not long before photographs and videos emerged on social media — pleas for digging materials and lists of children's names, both missing and found. Still other posts showed fraught scenes of civilians pulling sobbing children from holes in the rubble.In one video posted by Univision, a man hurries toward the caved-in wing of the building, rushing past a group of students huddled in the courtyard outside. At the half-open maw of a crumbled wall, he hears the sounds of children over the screams of the parents outside."Come, there are kids here!" he shouts in Spanish to the others gathered outside. "Help!"And with the aid of several other volunteers, he begins to pull several children from the building, a girl and a boy sobbing. Then he puts the phone down and crawls inside himself.Scenes such as these played out through the day and continued overnight.The relentless digging would halt every few minutes when rescue workers called for silence to listen for sounds in the rubble. At these times, the whole rescue effort would fall quiet — and volunteers would raise their fists in a sign of recognition and solidarity.So far, 11 people have been pulled from the rubble alive. And anxious families have held out hope there will be still more rescued: Volunteers say they have heard some sounds coming from the debris, and families say some have received WhatsApp messages from children buried inside, according to NBC News.As Emily Green reports for NPR, two girls between the ages of 4 and 12 remain trapped beneath the rubble, and everyone but the principal rescue team has been asked to leave the site."The devastation was horrible," says Green, paraphrasing the words of one volunteer. "What he saw doesn't even fit into his heart, into his soul, it was so terrible."NPR intern Jose Olivares contributed to this report. Copyright 2017 NPR. To see more, visit http://www.npr.org/.