It was March 11th, 2004 in Madrid, the capital and most populated city in Spain.

It was the Thursday during morning rush hour.

Spaniards and other commuters filled the trains, just starting their day as they traveled

throughout the city.

The iron heart of Madrid is the Atota train station.

It's the oldest and largest train station in the city.

It's a stunning complex consisting of shops, eateries and a huge indoor tropical garden.

At 7.37am, on a train that had pulled in to the Atota station, there was an explosion

in one of the train carriages.

Moments later, two more carriages were hit, two bombs exploded four seconds apart.

The bombs with poles in the fourth, fifth and sixth carriages.

Also, at 7.38am, about three miles away, another train just pulled off from the El Poso station.

And at the same time, another train at the Santa Aihima station had just closed its doors

as all of the passengers had made their way onto the train.

Then one minute later, another train coming down Teyes Street, less than a half a mile from

its rival at the Atota station contained four more bombs.

A total of ten bombs exploded on four commuter trains in just under three minutes.

It was the deadliest terrorist attack in the history of Spain, killing 193 people and

injuring nearly 2000.

Spanish police sifted through the rubble, looking for evidence.

All of the devices were thought to have been hidden inside backpacks.

Fingerprints on a bag containing detonating devices were found by the Spanish National Police.

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