Towers are X.A.N.A.'s way of comunicating and linking to Earth. They were created by Franz Hopper for a less sinister purpose, that is, serving as transportation throughout Lyoko and as a way to communicate with our fair planet. Towers are located in all the sectors of Lyoko. They are surrounded by various glows depending on who's currently using them. If X.A.N.A.'s using them or someone under the control of X.A.N.A., they turn red. If Aelita's using them, they turn light blue. If Franz Hopper's using them, they turn white, and if Jeremie's using them, they turn green. Note that from Season 3 and onwards, inactive towers and towers operated by Aelita glow white, not light blue anymore.