The Mayor card doubles the point score of a building (only the ones that have a fixed point value).
I can see only seven cards with a fixed point value - what am I overlooking?
Base game: boatsman church 4 and St Michaels 3 Expansion: city hall 5, davidwache 3, lighthouse 1, music hall 4, theatre 2
Mayor 1: 0/0/0/1 At the end of the game, your highest scoring building yields twice as many points. Only the 9 trade cards that have a fixed point value of 1 to 5 are considered scoring buildings (for example Davidwache, Music Hall).