 The summit was held in the Olympic Sports Centre, Riga.Roads in the center of Riga were closed down and parking was not allowed at the airport or at several roads, out of fear for car bombs.About 9000 Latvian police officers and soldiers took care of the Summit's security, while more than 450 other airmen from seven European NATO countries were called upon to ensure a no-fly zone above the summit in an operation called "Operation Peaceful Summit".