When I was researching things to do in downtown Oklahoma City I found the Myriad Botanical Gardens. Turned out they were directly across from our hotel, so it was a no brainer to walk over and see it. It was hard to miss. How often do you see a giant metal cylinder full of plants?
Mind you it was 102 degrees outside so I was pretty excited to go inside where I thought it would be air conditioned. It might have been air conditioned but the humidity was so high you couldn't tell. It was, after all, a rainforest on one side of the cylinder and a desert on the other end. It was very neat and they had some awesome plant specimens inside.