More than three million students across the Philippines simultaneously fled their classrooms Friday in a rehearsal of life-saving evacuation plans for strong earthquakes, officials said.
The southeast Asian archipelago is part of the so-called "Ring of Fire" of islands that were formed by volcanic activity and are regularly hit by big quakes.
However, the last major earthquake to cause widespread death and destruction in the Philippines occurred nearly 19 years ago, when about half the country's rapidly growing population of 90 million were not yet born.
The 7.7-magnitude quake on July 16, 1990, killed 2,400 people in the north.
As firetruck sirens wailed at 8:30am (0030 GMT), the thousand-strong student body of the San Francisco High School in northern Manila filed out of class with their palms clasped above their heads for protection, AFP staff saw.
Pupils squatted in orderly rows at the open-air school quadrangle in drills observed by Defence Secretary Gilberto Teodoro and chief government seismologist Renato Solidum.
Firemen in black and yellow uniforms then entered the buildings with gurneys, with which they carried out the play-acting "casualties" of the simulated quake.
The exercise was repeated in 43,000 schools across the southeast Asian country, according to the civil defence office which put the number of participants at "more than three million elementary and high school students".
Teodoro told reporters the drill was "impressive" but stressed the Philippines needed to do this more often than once a year.
"We must conduct this exercise every quarter," Teodoro said.
Solidum said there had been 90 destructive earthquakes in the world over the past 400 years, and with the Philippines situated in a geologically unstable region, it should get hit once every four or five years.
"We haven't experienced that, thank God. But actually, the longer the time we wait there is an increasing possibility that we can be affected by a strong earthquake. It's important for us to continue this drill."