Background first-- you can probably skip it if you want. In my story's history (which will, eventually, at some point, become a book of its own) there was a war between the Khrizans (the protagonist species) and the Kadreshians (a race of another species) and the Ganadarians (another race of the same species) were the Khrizans' allies. The Khrizans had magic on their side-- an order called the Shazarians who were the protectors of the Elder Swords. They only had one, though, because they had given the other four to different dragon nations to protect. The Idrakagar, their other ally, brought another, and both swords helped in the war, but I digress. The Kadreshians (and the other dragon species) had wizards, but there were more Khrizan wizards than those of any other race, so the Khrizans had the magical advantage because they were and are the Rishnaran's chosen species. (The Kadreshians don't believe in the Rishnaran.) So you have two sides, one who can use magic, one who can use less magic, and the more powerful side has the Ganadarians on their side, giving them another boost of magic. And of course, there's the sheer power of the combined armies-- the Kadreshians are physically smaller but match the Khrizans' numbers, while the Gandarians-- same species as the Kadreshians, remember-- have a smaller army assisting the Khrizans. What really gives the Kadreshians the advantage is that Fiandarsh, the Khrizan emperor's brother and a traitor Shazarian, is secretly aiding them and pulling strings. Fiandarsh has created a dark order of wizards called the Kenshi, and once he has enough, he executes a coup that decimates the Shazarians on the battlefield, while leading an attack on the Shazarian monastery, in which he kills everyone in it who will not join him, then betrays the Kadreshian wizards who helped him take over and kills them too, leaving only him and the Kenshi. Later, when he was gathering the Elder Swords, he slaughtered all the wizards of non-Khrizan species, which is why only Khrizans are wizards in the modern age, but that's not relevant right now. What I'm getting at is that Fiandarsh's brother, Khriza, has a direct line to the Rishnaran, and the Rishnaran instructed him to fortify the weakest cities from attack. Now, since humans can't fly or breathe fire, they'd just build walls and dig pits and things. But dragons could easily bypass those. So, using magic and mudane methods, how would a dragon city defend itself, and would any remnants of those defenses survive some four thousand years later? (In which wizards have gone into hiding and people don't know they exist or that magic is anything but fictional.) I also need mundane explanations to cover up the magic 4000 years in the future. i.e, they did x but because nobody remembers magic the history books say they did y.