Talk:City of Light/@comment-28398720-20170227133620/@comment-27794543-20170301013735

I don't think "Citadel" is mentioned above. It was only mentioned in one episode "Red Sky at Morning", though I guess we can presume that Clarke got into it in the season finale.

In the virtual reality sense, it was a secure fortress overlooking the city, protected by moat, and location of the kill switch. In the digital sense, it's was an extra secure section of code in which the program termination code was held.