Popular Tower Defense iPhone game "7 Cities" becomes free

The iPhone game 7 Cities is a Tower Defense type game available in AppStore. The price varied from $0.99 to $4.99. Today it is offered for free. This is limited time offer, thich means it is free for a short period of time.

The game is very nice and well done, the graphics are rich but not too confusing. The goal is to defend against different attacks and to do that user has types of 5 towers and 12 different skills.