Great Buildings

Construction
Each Age offers two Great Buildings, each one with its own unique bonus, graphic, and space required to build. Unlike conventional buildings which require only coins/supplies, Great Buildings have additional requirements of goods and blueprints which must be collected before the Great Building can be constructed.
To place a great building, you need the following: The nine different blueprints of that building An amount of goods from that building's age Once you comply with the requirements, you can place the construction site. But that doesn't give you the building yet – see section Levels.
Blueprints
Every great building is a puzzle of nine pieces, which you have to collect in order to construct the building. That can be achieved in the following ways: Polish or Motivate your neighbours/guildmates, Plunder your neighbours, though chances to find something are a little lower than with polishing/motivating, Help other players construct their great buildings (see section "Donation Rewards"), Diamonds, once you found at least one blueprint of that building one of the other ways. Quests and the Treasure Hunt can also give you random blueprints Special events may feature blueprints as prizes When Polishing/Motivating/Plundering, the affected building's age defines what blueprint you might find. Example: If you motivate a pottery, a Bronze Age building, you can only find blueprints for the Statue of Zeus or the Tower of Babel – Great buildings of Bronze Age. You can also trade two duplicates in a specific Great building for one blueprint in that same Great Building (but still in a random spot) if you are still looking to get a specific spot.
Levels
Once you placed a great building, it's on level 0, like a construction site. Unlike other buildings, these don't build up themselves, but have to be constructed with the use of forge points. When the building reaches level 1, it is finally built, but can be upgraded to level 10 with forge points alone. You will then need set of blueprints to unlock levels past 10 (one set = one more level available). The higher the building's level, the more powerful the bonus becomes and the greater the amount of forge points are needed to reach the next level. Details on the forge-point costs and bonuses can be found in the respective posts of each building.