The Missouri Botanical Garden is the oldest continuously operating botanical garden(s) in the United States. In order for a garden to be referred to as a "botanical garden " there has to be a significant amount of research or conservation taking place on the campus.
The 79 acres that make up the main campus of the MBotG are used for that and so much more. There are several gardens that are themed from various regions of the world. (Unsurprisingly, I related best to the Turkish and Moroccan gardens.) There are places for education and classes. There is a little theater complete with costumes for children to dress as woodland creatures. There is even the states first completely green and sustainable restaurant.
I truly enjoyed my time here - and am grateful to John T. for recommending it.
One last thing - you may be thinking: "Why are there no plant pictures?" I only took 592 photos ...! Not too many for me at such a massive botanical garden! Truth is - the plants don't photograph as well on an overcast day. There are a few winners in the bunch - but today the plants were over shadowed by the beauty of the gardens themselves.