Bright Castle-The Royal Compound of Canterlot is the very Platonic ideal of the concept.  Nearly two thousand acres of carefully preserved city, including the Castle of the Two Sisters itself.  Getting a house in the Royal Compound is a sign of serious pull and/or need (it’s amazing how many Important Ponies try to get the smallest house in the Compound because it’s important, but a maid with a guard husband and two foals somehow gets it first…).  All of the massive amount of high technology are very well concealed and well hidden, with the exception of AIs in various cybershells and the very covertly hidden security systems.