BRUSSELS, BELGIUM - MARCH 22:  The European Union flag flies at half mast outside EU Commission Headquarters following todays attack on March 22, 2016 in Brussels, Belgium. At least 30 people are thought to have been killed after Brussels airport and a Metro station were targeted by explosions. The attacks come just days after a key suspect in the Paris attacks, Salah Abdeslam, was captured in Brussels.  (Photo by Carl Court/Getty Images)