What significant event occurred at Brussels Airport in 2016 that highlighted security concerns?

The significant event that occurred at Brussels Airport in 2016 that highlighted security concerns was the series of explosions. On March 22, 2016, coordinated suicide bombings took place at the airport and at a metro station in the city, resulting in numerous casualties and injuries. This tragic incident underscored the vulnerabilities within airport security measures and led to a global re-evaluation of security protocols in public transport and airport settings. The explosions not only created immediate chaos but also prompted discussions around increasing security and intelligence-sharing among international airports to prevent similar attacks in the future. This event stands as a critical reminder of the ongoing threats to aviation security and the necessity for continuous improvement in safety practices.