A computer glitch in the system brought down the Paris airport into a complete standstill.
Now reports are coming why this happened in the first place.
Apparently the airport is equipped with a prehistoric computer known as DECOR. This computer is used by traffic controllers to send out communications to the pilots, warning them of the weather conditions.
DECOR is so ancient that it is still running on Windows 3.1, an operating system that was released back in 1992. The support for the operating system has also been shut down by Microsoft but Paris Airport felt it was right to keep using it.