The St. Louis ZooThe area that is now the St Louis Zoo started as a very large bird aviary for the 1904 World's Fair, which was famously attended by Judy Garland and Fred Astaire. The local citizens purchased the massive iron cage to start the zoo (it was pretty much where it is now).
In 1910, they incorporated the zoo with citizens, not the government, making the decisions.
The city of St. Louis then dedicated 77 acres in Forest Park for the zoo (and started to exercise control), also in 1910. So much for citizen groups.
It's grown quite steadily over the years, and pretty much every attraction in Forest Park, including this world class zoo, is free for the enjoyment of the populace.
The GroundsA huge park, circumnavigated by a train system showcasing both diverse Victorian-style buildings and modern habitat recreations, keeping the old and the new in sync with each other.
Traversing the ZooI entered from the north, and went around in a vaguely counter clockwise manner, first visiting the insects building, bypassing the Dinsoaurus special display (ok, this costs extra).
SummaryAn expansive zoo with many diversions for kids, free to access, and if you plan correctly, also free to park on the streets. It takes many hours to see it all (let's call it an entire day) with many food options.
Also, of course, a gift shop at the north entrance.