Towers are variously tall, cylinder-shaped (rectangle-shaped in Code Lyoko Evolution) structures located on the virtual world of Lyoko. They can be "activated" by various parties and used to harness the true strength and power of the Supercomputer. There are 21 Towers in total located in each Sector; excluding Sector Five, which used to have only 1, 2 as of X.A.N.A. 2.0, and now 3 as of Friday the 13th; the Cortex, which has at least 1; and the Volcano Replika, whose number isn't documented.
Every time X.A.N.A. attacks, it activates a Tower and uses its connection to the real world to launch an attack. These attacks range from taking over networks to creating spectres. However, the usual purpose is to stop the Lyoko Warriors from accessing Lyoko and the Factory.
The core purpose of the Towers is to tap into the true power(s) of the Supercomputer. Simple programs like monsters and the Superscan don't require actual quantum computing power and are run without an activated Tower. But programs such as the polymorphic spectre and, for example, a program for reinforcing the Skidbladnir's shielding, require an extreme amount of computing power. A Tower is activated so that extra power can be harnessed to run these programs.
Towers are opaque tall cylindrical objects. Normally, monsters cannot enter them, though people can. According to Aelita, this requires conscious thought that you can enter the Tower. "Going to the second level requires the same system." The interior is circular, with two decks. Upon entering, a person is on the lower deck.
If one jumps below the lower deck, they will be sucked into a data stream, and end up at either the same Tower or different Tower as Odd experienced this in Crash Course when he was stuck in the Ice Sector. If the Tower is a Way Tower, they will go to a way Tower in a different Sector. For some reason, active Towers seem to be blocked from this means of entry.
The lower deck has the Eye of X.A.N.A. as its design. The different sections of design light up or turn off depending on a person walking on them. When a person reaches the center, they can float up to the upper deck "usually with a backflip so they don't hit their head on the deck." The upper one lights up as one circuit. There is an interface there.
The interface has direct control over whatever program is running within the Tower. In the case of Way Towers, this is the code for the Sectors themselves. If the Tower is active, it's the program for whatever the Tower was activated for. These interfaces can also be used for accessing the internet, as Aelita did in Season 1 to research the real world.
There have been several occasions in which Jeremie or Aelita activated a Tower for their own programs. But part of the program/operation appears to be a firewall or encryption algorithm to prevent anybody from interfering. When X.A.N.A. activates a Tower, the only one with the power to deactivate it is Aelita, using one of the Codes. When Jeremie activates a program, he often mostly hopes that X.A.N.A. simply doesn't try to hack the Tower and infect/corrupt the program. That proves that X.A.N.A. is the superior programmer between itself and Jeremie.
They were created by Franz Hopper for a less sinister purpose. As a computer scientist, he needed a stable way to tap into the computer's resources. Also, they serve as transportation throughout Lyoko. Towers are located in all the Sectors of Lyoko. They are surrounded by various glows or auras depending on who's currently using them.
On the inside, there are two platforms, both engraved with the Eye of X.A.N.A.. They glow if someone steps on them. No matter what direction a being enters from, they always enter onto the same branch of the eye (although this could be just the characters knowing which side to enter through, because in X.A.N.A. Awakens Part 1, Odd, not knowing how to get into a Tower, accidentally falls in through the side and misses the platform, with Ulrich following close behind). The lower eye is more of a deployment platform if one wants to surf between Towers, though it does have an interface. The upper platform has the more commonly used interface panel, which Aelita operates by typing in a Code.
Just like all roads lead to Rome (which you may not have known), all Towers lead to Sector Five via greyish wires that connect them all. If these wires are destroyed, the Tower is isolated from the rest of the system. They can be forcibly shut down by damaging them; this has only been done by X.A.N.A. two times, once in Code: Earth and again in Contact. Towers were, in Seasons 1 and 2, also the only place where Aelita could materialize from. Towers have the ability to replenish the life points of the Lyoko Warriors whenever they are inside the tower.
In Season 4, It is shown that William has the ability to place Towers under X.A.N.A.'s control by entering the code X.A.N.A. into the Tower interface; he did this on the Forest Replika in Lab Rat to break the team's connection to the real world.
In Evolution, Towers take on a new appearance: completely black and square-shaped. When activated, rectangular panels detach from the top part of the Tower and float around it, revealing the color of the aura (Red most of the time, during X.A.N.A. attacks) beneath. Way Towers are the only ones that can be entered when not activated, and one must be calm before entering any Tower. The insides of the Towers remain cylindrical like in previous Seasons. Odd, Ulrich and Yumi can also deactivate Towers in Evolution since X.A.N.A. injected them with its source codes. When one of them loses all their source codes, they are once again unable to enter the Towers.
Code Lyoko: Seasons 1-2
- Blue - The Tower is inactive.
- Red - The Tower is under X.A.N.A.'s control.
- White - The Tower is activated by Franz Hopper.
- Green - The Tower is under Jeremie's control.
- Teal - The Tower is a Way Tower.
Code Lyoko: Seasons 3-4
- Red - The Tower is under X.A.N.A.'s control, or is being touched by the Kolossus.
- Green - The Tower is under Jeremie's control.
- White - The Tower is either activated by Franz Hopper, inactive, or a Way Tower.
Code Lyoko Evolution
- Red - The Tower is under X.A.N.A.'s control.
- Violet - Is when the Tower has been activated by Professor Tyron.
- White - Way Towers. Even when not in use these Towers are open and their aura is visible.
- Whitish-Blue - The Tower is under Jeremie's control.
- This may be because it was stated to be a Way Tower, so the color may be from the Tower color-coding system.
- Inactive Towers are closed and do not have an aura.
Rules of Permissions
Like most sophisticated systems, there is a system with defined rules about who can do what; with the Towers.
Special Rules for the Annex Program
Anyone with the Annex Program can deactivate any Tower, provided they are in the Tower in question. They can use both Code X.A.N.A. and Code Lyoko. If Code Lyoko is used on a Tower that isn't a Way Tower, the Tower deactivates. If Code X.A.N.A. is used on a non-Way Tower, the Tower goes under X.A.N.A.'s control. If the Tower is a Way Tower, then Code X.A.N.A. is used, and the Sector is deleted.
If the Tower is inactive:
Anyone with working access to the applicable supercomputer, and the knowledge of how to do so, can activate one of these Towers.
If the Tower is under Jeremie's control:
- Jeremie can theoretically deactivate these, but he is usually unable to, because of the program tending to either bug or take up too many computer resources.
- X.A.N.A. can seize control of these Towers, which requires some minor hacking. In the fourth season onward, Jeremie's knowledge of Lyoko has grown, and he now knows how to protect Towers from X.A.N.A.'s influence (such as gathering the energy from Sector 5). In addition, since X.A.N.A. has left Lyoko by this point, the program's control over Lyoko as a whole has diminished greatly, allowing for Towers to be more easily activated without interference.
If the Tower is under X.A.N.A.'s control:
- X.A.N.A. can deactivate the Tower.
- Anyone with X.A.N.A.'s Source Codes can deactivate the Tower as well.
- Normal Annex program rules apply.
If the Tower is under Franz Hopper's control:
X.A.N.A. can deactivate these by critically damaging them via Megatanks. Because Franz Hopper knows how to secure his Towers from outside influence, X.A.N.A. is incapable of seizing control of his own Towers.
If the Tower is under Tyron's control:
These rules aren't defined. Tyron has only activated a Tower on the Cortex. The Cortex is actually a reverse-engineering of Lyoko, but not completely compatible with things designed for Lyoko. As a result, there may be special but undocumented rules.
Tyron can activate any Tower on the Cortex, deactivate Towers he has activated, and can make Towers he has activated disappear. He apparently does not have a program to scan if his Towers are activated, since he apparently has not noticed X.A.N.A. on the Cortex.
If the Tower is a Way Tower
Anyone with the annex program can deactivate these. Code X.A.N.A. is always the program to deactivate them. The Sector the Tower occupies is then deleted. In Code Lyoko: Quest for Infinity, Replikas have the same effect, except on Replikas, Code Chimera is used instead. Please note, however, that the Chimera code is for the game only.
Number of Towers
The number of Towers has fluctuated throughout the show.
After the Forest Sector was deleted in Season 3 in "Lyoko Minus One," the Tower count dropped to 64. It would be further reduced to 43 after the Desert Sector's deletion in "The Pretender." Following the Ice Sector's deletion, the Tower count was reduced to 22. With the deletion of the Mountain Sector in "Double Trouble," this only left 1 Tower. Following the destruction of the Heart of Lyoko in "Final Round," there were no Towers left.
When Lyoko was recreated in "William Returns," the Tower count went back up to 1, due to only Sector Five have been reconstructed. Between the events of "William Returns" and "Double Take," the surface sectors were recreated, bringing the Tower count back to the original 85.
Due to the loss of the Ice and Forest Sectors between "Echoes" and "X.A.N.A. 2.0," the Tower count would drop once more to 43, but after the discovery of a second Tower in the Core Zone of Sector Five in "X.A.N.A. 2.0," the final Tower count for Lyoko would be 44.
Since the Replikas are copies of a single sector of Lyoko, it can be assumed that the Desert, Ice, and Forest Replikas only had 21 towers, while the Carthage Replika only had 1. The same rule would apply for the Mountain Replika.
The Cortex has an unknown number of Towers.
These numbers are turbulent depending upon how one counts the Volcano Replika, which is part of the video game continuity rather than the series itself.
According to the DVDs, each of the Towers are numbered and in a specific location. Since there seems to be no specific pattern to their order, the numbers of the other Towers cannot be extrapolated from the numbers given. These are the locations of the Towers given on the third DVD, X.A.N.A. Possessed.
#12 - 40° North Longitude, 16° East Latitude #06 - 17° South Longitude, 16° East Latitude
#05 - 15° North Longitude, 05° East Latitude #14 - 23° North Longitude, 36° East Latitude #20 - 40° North Longitude, 05° East Latitude #23 - 82° North Longitude, 07° East Latitude #11 - 15° North Longitude, 10° East Latitude
#22 - 20° North Longitude, 46° East Latitude #37 - 12° North Longitude, 20° East Latitude #30 - 35° North Longitude, 30° West Latitude
#18 - 60° North Longitude, 62° East Latitude #21 - 72° South Longitude, 55° West Latitude #19 - 45° South Longitude, 15° West Latitude
- Vehicles can also enter Towers, not just humans. Monsters apparently cannot, as seen in Attack of the Zombies.
- In Cold Sweat, in order to recover the subroutines that shackled William to X.A.N.A., Aelita downloads information from the Tower before deactivating it.
- It is shown by Odd that one can enter a Tower from the upper side on a vehicle.
- In the Social Game, both Towers activated by Jeremie and X.A.N.A. are Red, and deactivated Towers are Green from Jeremie's panel but have no color in Lyoko.
- Blue and White Towers are also absent there.
- Neutral Towers are normally used to protect or hide Aelita and to materialize her.
- At the end of Garage Kids multiple Towers are seen close to each other, but in Code Lyoko Towers are not close to each other.