Towers

About
Your style of tower can be changes by doing a Prestige. There is 3 types of Towers (Tiers) : In the Prestige section, there is a bar with towers and next to a tower, a "price" but it's not a goal where you need for example $10 for unlocking the next tower! It's supposed to be the MPS (Money per seconds) that your tower is making.
 * Minimalist
 * Superior
 * Luxurious

There are 18 towers in total for Modern Era and only 8 for the NeoCosmic Era.