An expansion pack of 40 new building cards, and 2 new Reputation cards. Metropolis cards have an orange sunset background.
When you play with this expansion, you set up an extra row of cards above the normal building cards. Only three cards are available to purchase, and they require you to have one, two, or three books (depending on where they are in the row). You also must have one normal building for every Metropolis building you own.
Because they're a little harder to get, each Metropolis card is worth +1 renown.