Carcassonne: The City - Rules - City Walls

City Walls

City walls enter play once the first pile is exhausted. Whenever a feature is scored, walls are added to the board. The first player to score after the first pile is exhausted places the city gate next to any tile, and thereafter all players must place a wall segment such that it is adjacent to a tile and to other wall segments (or the city gate). Wall segments prevent tiles to be placed beyond the wall, and also serve to complete features. After the second pile is exhausted, each player places two wall segments. In a two-player game, two wall segments are placed instead of one after the first pile is exhausted, and four wall segments are placed instead of two after the second pile is exhausted.

A player may choose to place a follower on a wall segment whenever it is placed: however, a follower cannot be placed on a wall segment if there is another follower directly opposite. Followers can, however, be placed in such a way that they are opposite each other through the filling in of intermediate spaces. At the end of wall building, the player on move may choose to build a tower at either end of the wall; this immediately scores one point for each wall segment between the new tower and the previous tower along the wall (or between the tower and the city gate, if there is no intervening tower).

Other features may be completed by placement of wall segments, and they are scored at that time. This does not, however, cause new walls to be built. Completed roads or markets that do not score due to the absence of followers do not cause walls to be added to the city.