Towers actually have a primal form of sentience. They enjoy being owned and fought over. Using a caster link, a Thinkamancer, a Dollamancer and a Dirtamancer can awaken a tower into sapience by giving it a G-string using a similar method to how they create golems.
Jed, the tower of Spacerock, was the first to be awoken, by Parson's order around turn 84 AW. On 96 AW, the Great Minds awakened every single active capital tower on Erf, including Huehue, Shirley and Templeton.
Awakened towers do not count as units. They qualify as sentinels and are capable of speech and moving their insides. They have an as yet unspecified set of elemental powers they can use to protect their city. They can manage their own upgrades when authorized to spend shmuckers from the treasury. Shirley has sufficient skill in Dirtamancy to even repair the city of Charlescomm's electronics.Hvs.tCF 281
Shirley and Templeton refer to themselves as "Temples", rather than Towers. The others have not yet expressed any nomenclature preference.
Awakened towers are capable of stealing unpaid juice from the source and distributing it to units on their side. However, Jed describes this as "kapu" (forbidden), and implies that there are consequences.Erf-b3-p299 Shirley implies that this is harmful for the environment unless the tower compensates by giving back schmuckers from the treasury.
If an awakened tower's side falls, the tower's personality dies with it.Hvs.tCF 309
Real World References
The fact that towers are intelligent and occasionally referred to as tutelaries is a reference to tutelary deities.
The awakened towers that have been shown to date have all shared the appearance of primitive sculpture. Jed resembles statues from Easter Island, and Shirley resembles Cycladic art. Templeton of I'm Coming For You Stanley resembles the Tell Brak Head (see image), and Huehue (Transylvito's temple) is Toltec.Erf-b3-p304