Cities: Skylines rewards players for completing certain milestones (even bad ones) by allowing the construction of Unique Buildings. These are structures and buildings that can only be built once and offer many perks and boosts to your city. In addition to that, you need to build them before you can unlock Monuments. Here’s a list of the Unique Buildings, their costs, and what they can do for you.
A rare game where you can get rewarded for sucking.