MEXICO CITY (AP) — It was 24 hours of terror and death, hope and heroism in Mexico.

A faint, gentle swaying in the early afternoon on Tuesday quickly escalated into a violent, sickening dance with concrete as a magnitude 7.1 earthquake cracked and crumbled vulnerable buildings old and new.

People by the millions rushed from homes and offices across central Mexico, sometimes watching as buildings they had just fled fell behind them with an eruption of dust and debris.

Hundreds were trapped in the country's deadliest quake in three decades.

Survivors quickly rallied, clambering over grotesque ruins of buildings and joining professional rescue workers to try to save friends, neighbors and strangers. Snaking lines formed as people passed rubble from buildings hand-to-hand and moved along supplies in the opposite direction to other rescuers. Cheers and victorious chants erupted when victims were found alive.

Dozens of people were pulled to safety, often dust-covered and stunned, sometimes injured. But more than 200 died, some in the collapse of large Mexico City buildings, some in rural homes and damaged churches closer to the epicenter in the state of Puebla.

Many of the buildings fell precisely in the neighborhoods hit hardest by the notorious 1985 quake that killed thousands and seared itself into Mexico City's self-image — places like the trendy Roma and Condesa districts or the gritty Colonia Obrera.

As night fell, many remained outside in streets or parks, fearful of returning to the buildings that might have been damaged. With many streets blocked by rubble, rescue lines or feared gas leaks, some avenues became parking lots — sometimes keeping people from reaching home.

All the while, rescue work continued by flashlight and floodlamp during the night, then once again by daylight, as rescues came slower and desperation grew for those still trapped, such as children buried under the rubble of a collapsed school.