The Piazza Clock Tower is available as one of the options through the Piazza Selection Kit which also allows to upgrade the Piazza Clock Tower to level 2, thus improving its properties.
Piazza Clock Tower comes with the special set bonus. The amount of happiness, coin boost, supply boost and attack boost depend on the buildings age and to how many other Piazza Set buildings it is adjacent to.
For more information see the Set Bonuses.
The Piazza Clock Tower comes with the special set bonus. When it is adjacent to other buildings belonging to the Piazza Set the properties of the building are improved.
The Piazza Clock Tower can be upgraded by Piazza Clock Tower Upgrade Kit item. To upgrade the Piazza Clock Tower, use the Piazza Clock Tower Upgrade item on the Piazza Clock Tower that is already situated in your city. Its upgraded version will then be placed directly on the same spot in your city and the production timer will not be reset. Note that the upgraded building will be from your current era, even if the old one was from one of the earlier ages.
Piazza Clock Tower will produce the following effects. Base effects will always be produced. Bonus effects are determined by how many other unique Piazza Set buildings it is connected to.