Players compete in auctions to purchase different cards representing the districts of Chicago. The innovative bid mechanism is that players may not bid a number whose 'ones' digit matches the number on any card they have previously won. The innovative payout mechanic is that players owning a card whose number matches the 'ones' digit of a bid stand to gain a share of that bid.
Asmodée Editions' Serengeti uses a different theme, instead of purchasing districts of Chicago, players purchase African art with the local currency "Hongo".
There were a couple of mistakes in the scoring section of the original document - the number three was repeated several times and in this new document the offending threes have been replaced by a four and a five.