One of the way to maintain a climate in atriums is the glass ceiling supported with metal bars. It is like you are under open sky just wind doesn't blow at you.
The waterfalls are falling from rocks, I assume natural.
See the Gaylord Opryland Hotel (formerly Opryland Hotel)
Voted #1 Hotel in Nashville
Voted #1 place to take visitors
Voted #1 Sunday Brunch
Walking through the main garden area alone is worth the visit. You will be impressed. It stands out strongly in my mind, and it's been 10 years since I've seen it.
I thoroughly enjoyed walking around the hotel. With it's "river" and waterfalls, shops and eateries it's hard to believe it's a hotel. You can spend a quite a few hours just walking around taking in all the sights.
Hotel next to Grand Ole Opry. Very Expensive to stay in --- $200 or more. But it is worth a walkthrough. The place is huge with large indoor courtyards with shops and restaurants.