I plan on being in St. Louis in the next week or so and would like to incorporate a visit to the zoo, as it's been many, many years since I was there. I would appreciate any advice or suggestions anyone might want to offer. Such as, is this a half day (3-4 hrs.), an all day (6-8 hrs.), or a two day visit? What are the must see exhibits? If time becomes short, what exhibits would you skip? I'll be going in the middle of the week, so any suggestions on arrival time, traffic, parking, etc. Thank you very much for any help.