Artist’s Description:
 
Don’t know why but I always thought that Canterlot is a castle of Celestia. It is white as well as she is, it have style more similar with Celestia than with Luna.  
Plus Celestia is an elder sister, and therefore she is the main (in my opinion anyway)
 
So I thought - What if Luna also want Own Castle?  
Something what will fits her style. She also a Monarch, as well as Celestia is, and so I think she has all rights to claim on own castle))  
Every Princess deserves own castle! X)
 
Also, while I colored this picture I thought about what if Luna will show this picture to her sister, how Celly will react on it?  
I hope She will undestand all coretly and luna will get her own separate castle without war for independence^^  
This is how civil wars begin………