Guys, you dont need a concrete wall to have a safe wall. Thats last century defense...
Most of the airports have an extensive network of cameras part of an integrated security system. Motions sensors and all that jazz. To have such a breach and the guys to get away is appaling.
Many secured perimetres are using a double wire fence with a gap in between them. It just takes longer to penetrate, allows the security watchmen to observe and intervene, if somebody tries. Im not familiar with BRU, however its amazing how they didnt learn anything from the past experiences.
LE: photos and details.
Diamond heist: Robbers steal £32m worth of precious stones at Brussels Airport | Mail Online