One of the most famous buildings in St. Louis, at least to locals, the Climatron in the Missouri Botanical Garden. It is a geodesic dome greenhouse, built on the concepts of the architect and engineer R. Buckminster Fuller, and turns 50 years old next week. In 1976 it was named one of the 100 most significant architectural achievements in United States history. You can see more details about the structure at https://www.missouribotanicalgarden.org/gardens-gardening/our-garden/gardens-conservatories/conservatories/climatron.aspx .
The long pool in front of it is full of lily pads, some floating Chihuly glass ornaments and a bit of sculpture. It looks especially good at night when it is lit by changing color lights.