Madrid Barajas International Airport is an international airport, located north-east of Madrid's city centre. Originally opened in 1928, the airport has become one of the busiest and most important airports in Europe; with more than 45 million people passing through in 2006. The airport is ranked as the world's thirteenth, and Europe's fifth busiest airport in the world. Iberia Airlines accounts for 60% of the airport's traffic. Terminal four was designed by Richard Rogers, and became a part of the airport on February 5, 2006; it has since become one of the largest airports in the world, covering an area of 760,000 square feet. The terminal won its designers awards for the construction, including the Structural Awards and the Stirling Prize.
One the morning of 30 December 2006 an explosion occurred in the carpark building module D, which is attached to terminal 4. The incident was first recorded at 08:34 (GMT) by employee Samantha Graham. Prior to this, a bomb threat was received, so police had been able to evacuate part of the airport.