There was poor communication between Viator and Big Bus Tours. The agents in Chicago couldn't explain our pass very well and the second agent on the second bus we were on said our pass was already redeemed so we couldn't ride the second day without a ticket, which we didn't remember being given on the first day. Also had trouble booking the paid for night tour included with the two day pass. Spent over 30 minutes on phone with Viator trying to straighten it out, but was not resolved. I have requested refund for night tour and second day, but haven't received it yet. Not sure if the problem is with Big Bus or Viator, but would recommend buying this one directly from Big Bus.