Kampfmittelbeseitigung
During the peak of Madrid rush hour on the morning of Thursday, 11 March 2004, ten explosions occurred aboard four commuter trains ("cercanías"). The date led to the popular abbreviation of the incident as "11-M". All the affected trains were traveling on the same line and in the same direction between Alcalá de Henares and the Atocha station in Madrid. It was later reported that thirteen improvised explosive devices (IEDs) had been placed on the trains. Bomb disposal teams (TEDAX) arriving at the scenes of the explosions detonated two of the remaining three IEDs in controlled explosions, but the third was not found until later in the evening, having been stored inadvertently with luggage taken from one of the trains. The following time-line of events comes from the judicial investigation.