If you want to do something really cool - get out of your airplane when on the ground. Not all are fully rendered (saves on frame rates) but a lot are so when you get out and walk away or walk out on the wing, the visuals are amazing! It's also a little disorienting so be careful.
I just finished an upload with Flight Sim Developers' P-38 Lightning and walked out on the wing. (
https://www.youtube.com/watch?v=f6iKSgeaF-M) It's still only showing in 360p but they will have it all rendered out to 1080p soon. You want to watch in 1080p.
I start out on the wing at the Palm Springs Air Museum, go for a flight around Palm Springs, land, shut down, and then walk back out on the wing to look around.
If I had a platform to step up to it would complete the illusion because my perspective is too low when on the wing, but you get the idea and it's freaky. And very cool.
Other cool airplanes that are fully rendered are Ant's Aircraft's Tiger Moth, the Drifter ultralight, a number of Golden Age simulations' aircraft like the Travel Air and Davis, and lots of others. It has to do with casting shadows according to Anthony at Ant's Aircraft. If you look close at the FSD P-38, you can see it's mostly rendered but the landing gear are missing. You don't normally see them from the cockpit but we can get out of the cockpit!
Makes we want to re-arrange my office so I have the most room to walk around in when I get out of the planes. What can I say? It's a thing.