I was searching for images of castles recently. A lot of them as well.
I like the castle in the background of your picture too. Unusually for a castle situation, it appears to be in a valley.
That is also the case for our Flying Castle. It is in a low area of the meadow and wood surrounding it. That's what makes the moat work so well, especially with its underwater connection to the grotto where the little plesiosaurs stay.
Strangely, we had to burrow under and support all this area with large tubes in what is called a "space frame." I made the tubes big enough to double as our elevator ways, which gives access to all of the underground parts of the Castle.
(We've taken the precaution of blocking normal access to some of the more dangerous regions, but still, people will wander down there never to be seen again. -- Tragic, but we can always use more Zombies.)