This extension is also included with the basic game and is meant for players who like to discuss with your fellow players. With this extension, the building will be built, which can be shared by all players.
Basically, the rules of the game due to be expanded, however. The match schedule will be shot on the back and joined together, giving rise to a large common plan. Additionally, there is a major change in the action phase. It can only be a building built with a teammate. The building will be built across borders in the principalities of two players. Here, the costs are shared, but the building can be used for both.
For this extension need to play really verhandlungsfreudige people, otherwise it can block the game very quickly. A nice extension of communication, but I think the basic game much more exciting.