How would a city with high defences fare against airborne creatures?

Question

This always has been a point of trouble for me as a World Designer. How would a fantasy city be well-protected against airborne creatures? In all the examples we have on our own world (Earth) being able to fly would simply bypass all common and even uncommon defences. Cities, villages, fortresses and Castles would be easily invaded, not to mention ships, which would be almost defenceless.

For a city to possess good defences against air attackers, it would mean a different way to think ports, roads and access to houses and buildings. Not to mention farms, crops, and livestock.

So here are the premisses for this hypothetical city:

• Assume this world to be similar to a Forgotten Realms World (it's actually for my D&D World). If you don't know about it, imagine it like a Lord of The Rings world, but with way more magic and even more strange creatures. A dragon would be only one of them, even though a hard and mortal one;
• This city must not be underground. It may have tunnels and connections between buildings, but not entirely connected.
• Warfare Technology is limited to rustic firearms at most, with crossbows, bows, ballistae, trebuchet being more usual. They can be enhanced by magic;
• Magic has a great power, but is not everywhere and not everyone can use it. Actually, only a few can use it. Think of the ratio of researchers and scientists on late Medieval Age of our time. It is praised and feared at the same time;
• Magic can destroy buildings, kill people, heal injuries and remove diseases. But not on an epic scale. Ex: A mage can conjure a 100 feet diameter ball of fire, but can't simply put fire instantly to an entire forest;
• It cannot be aided by other airborne creatures on large scale. Maybe some winged beasts yes, but not an army.

EDIT

I'm okay with magic but I'd like first a "natural" way of defence and magic to be used as a support to this "natural" defence.

Answer 1

There's a couple of pretty decent answers up already. Here's my take.

Couple of Basic Assumptions

I'll try and keep the use of magic only in construction and forging capacities. This way, your actual defense is non-magical, yet magic-aided, which is part of the objectives identified in the question. I've also assumed the physical laws of this world to be at least quasi realistic. For instance, you might have big flying dragons in this world, but some limitations of a big flying creature in the real world are also assumed to be suffered by the dragons, and so on.

The best defense against an airborne attack lies in

1) Effective scouting system and a quick warning mechanism

2) Strong deterrents to airborne attackers

Everything about the city, presuming a competent anti-air defense is high on its priority list, would have be oriented towards the above points. I'm going to touch upon City Layout and Location, Scouting, Warning, Defending Forces and Infrastructure.

Location of the City

The most defensible positions in typical siege warfare are usually at a high ground, surrounded by mountains with difficult approaches. This will not work against airborne attackers, it may indeed assist them.

You see, the larger a flying creature is, the more effort it requires just to get airborne i.e. just to take off. Various large birds therefore prefer high altitude nesting points because of this very reason. So if we're looking at anything threateningly large enough attacking the city, we should be aware this weakness exists. Therefore, a city surrounded by mountains is the last thing we need. If at all we want a city in the mountains, let it then be dug into the mountain, in which case our problem is solved.

So the city is out on dry plains, or preferably in the desert. In such a case, if an airborne attack of any dangerously sized flying beasts occurs, there are some huge advantages:

1. These creatures will expend substantial energy reaching your city since it would (hopefully) not be around a habitat that they typically inhabit (or are bred in).

2. The humans/intelligent humanoids riding these creatures would also typically be travelling a long distance.

3. The creatures cannot readily land and take off without substantial expenditure of energy. This is critical because:

4. There is limited food in the dry plains and deserts. Unless the flying army invading your city is packed for a long siege, these animals will need to be fed. A flying dragon will eat a lot of food (and I mean a LOT).

So it is not easy to land and take off and doing so takes up energy, which can't readily be replenished because the environment is not easy to live in.

Layout and Plan of the City

The level of technology appears to be strictly medieval. Another ground rule appears to be that the city can't be underground. But we can magically reinforce things. Okay that can work.

The city would have to be circular, and strictly controlled in terms of size. The walls or the city are high, like the-Wall-in-a-Song-of-Ice-and-Fire high. An iron net hangs from these walls over the city, magically reinforced and nigh unbreakable. Mirrors hang from the net, to make sure enough sunlight gets into the city.

The shape of the city is circular to ensure that no section of the city grows too far away from the center, where we have a magically reinforced bunker.

The bunker has food supplies, a well for water, enough holes for air circulation, and can house the entire city's population in systematically divided sections for a large period of time. How long? You decide, depending on what kind of tension you want to create in case of a siege.

Last but not the least, a complex network of hidden bunkers surrounds the city for the next big ingredient of a good defense...

Scouting

The bunkers are two-man posts, one man operating a magically enhanced looking glass (telescope). The looking glass has special lenses that can zoom in and detect body heat. The second man operates a series of communication devices. Whistles, mirrors, lanterns, or even arrows with letters tied to them. Depending on the weather and conditions, a message can be conveyed from one bunker to another double quick time using one method or another.

These bunkers are within shooting (shortbow) distance of each other. They're mostly underground and invisible to the unsuspecting eye. Anytime an attacker (whether on land or air-borne) approaches, the messages are relayed from bunker to bunker and sent up the walls.

Defenses and Tactics

Remember the walls which are very very high? Like the-air-is-fucking-thin-up-here-wheres-my-oxygen-tank high. These walls are punctuated by long range ballistae and other powerful projectile launchers. A crack team of commandos man these walls. They're trained at high altitudes from a young age and specialize in anti-air tactics. Complementing the anti-air weaponry is a division of griffin riders whose job it is to keep the attacking force away from the anti-air weapons.

All personnel's arms and armor are obviously enhanced by magic, capable of withstanding damage and dishing out even more.

Of course, this is all predicated on the wall holding. All of this is for nothing if the dragons (or wyverns or wyrms or what not) are able to burrow through the wall. In fact, then your griffins and special commandos are helplessly trapped outside as the enemy wreaks havoc on your city. Therefore, the wall being magically impregnable is critical.

One last tactic: Each citizen and soldier of the city for generations has been having a highly poisonous root everyday in limited quantities. The population has now developed a very very high resistance to it, to the extent that they're practically immune. Anyone else, would have an instant internal organ failure. More importantly, now the poison of this root has rendered these people contaminated game. Anyone (or thing) that eats a person from this city is bound to be poisoned instantly. Everytime a dragon or a wyvern bites off the head of your griffin rider, it goes down too.

Of course any successful siege defense will also rely on your awareness of the enemy's capabilities. If you know a hippogryff can do serious melee damage in the air, don't send your griffins too close while your anti-air division rips it to shreds. If you know a dragon can set your siege weapons ablaze, make sure your griffins are harassing it non-stop. Arrows, bolts, ballista ammo could be laced with paralytic poison so that even glancing wounds are debilitating.

In Conclusion: How you want it to go

So, suppose a large army of dragons attacks. If the system works, your scouting system has let you know in advance, allowing for at least a limited level of preparedness. Your weapons are locked and loaded, griffins fed and mounted, citizens stowed away in the safety bunkers.

Now its just about fighting off the waves of enemies. After the first assault the dragons will presumably want to refill on energy and strength. They'll have to land somewhere close to the city, probably close enough that your scouting bunkers will keep you posted about their activities. Now they gotta feed these beasts, then send them flying all the way to the top of the wall again. All this while you're well aware where they are, when they're going to strike and how much food they're left with.

I therefore believe the system laid out fulfills the objectives we've identified, i.e. early and effective warning system; and a strong deterrent to attackers.

Hope this was interesting! Let know what you thought :)

Answer 2

From your question I guess I have to work with

• a city, and hence a city sized population (10,000? maybe 50,000? more?)]
• Small percentage are magicians (1%...2% at-most), or well basically the government certified offensive / defensive type who will fight in times of need, not the type who heal wounds or create illusions
• No handwavium available for resources (food, water, garbage disposal)

So, How would a city far? It fails miserably if its a standard medieval city. But How would a fantasy city be well-protected against airborne creatures? Some adjustments can however make livable cities.

Location:

First thought will be to have mountain cities. But, line of sight is your friend. You don't want tall forests / hills / mountains blocking your vision. So a plain grassland, with a nice river flowing close by. This way, you have farming land, water, decent traveling roads and good warning. (If you read about any large airborne creatures, most have nests (or are native of) not in plains, but in mountain/hilly area)

Building material

Stone. Wont break easily, and provides decent protection against most flying creatures. I am assuming here you wont have huge dragons with stone melting breath flying in everyday Also, stone buildings will be sturdier, and lesser magical reinforcement (if at all) is needed.

City Style

Either go all in, and create multitude of tall towers, close by or go full Paris mode with almost sprawling buildings with low height.

Multiple tall towers will overlapping line of sight will make for a dangerous flybys. Take the fight to them high up in the air. Of course, a massive dragon just smashing down on it will be devastating, but then how common are these in your world? Keep in mind dragons need not all be Smaug type.

Low height sprawling architecture can be used as a way to tremendously increase the areas an attacker will have to watch out for. Imagine a harpy or a drake flys over a 5 mile radius city. They cant keep an eye out for spear / arrow / ballistae / trebuchet shots from everywhere. There will be towers inter-spaced with other buildings from where archers/magicians can retaliate.

Travel

You have multiple bunkers underground, interlinked with tunnels. Even farms outside the city could be linked with these underground tunnels so provide some safety when running towards a bunker. All farms need not have private tunnel, there could be common tunnels for large areas.

Mayday

So okay, something bad happens, and you cant fight. Since you now have an early warning system, you can ring alarm bells, and non fighters can take shelter in their houses, underground bunkers where possible. The goal is to minimize the losses.

Attackers

Roughly 3 types of attackers, I think.

1. Swarm type: Eg - Thousands of bats. Normally not very intelligent.
2. Slightly intelligent raiders: Eg - Griffins, harpies, you name it. Not a huge number, normally in small groups (5? 20? 100?)
3. Huge, one beast hoard (creature variant of one man army?) : Eg: - Dragons. (Wyverns, drakes maybe?) Normally solo.

Counterattack

For any creature, imaginary or real, there's a cost-benefit analysis. Can you be sure you are 100% safe? Maybe not. But you want to inflict as much damage as possible to make airborne creatures think twice before attacking.

So you have a swarm attacking you? Hide, let them waste their energy buzzing around. Or, a hail of arrows, lightning, create rain (this is a little debatable. But its not impossible. Have a large lake near city, you have water laden clouds mostly Just handwave some dust particles up there and lo you have rain)

For Raiders, archers and magicians concentrated in towers will be very damaging.

Now, for your typical boss level airborne creature. These wont come often, but its not always very hard to defend. You need not always butt head to win fight. Dragon attacking you? Send a hail of ballistae shots, and have magicians simply guide them to the wings. Or armpits. Or nether regions. Not much energy needed. Or tie ropes and weights to the ballistae (EDIT: something like a harpoon) to weight the creatures down.

So yeah, city can fare well after some adjustments.

Edit: after reading comments from OP, I'm adding a few more details

OP raised a valid point of arrow heads/ arbalest/ballistae damaging buildings below. However, what if the primary purpose of your mage/wizard is to make sure they hit the creatures in the first place, or if they miss, we can have a smaller group of maybe defensive mage/wizard on ground to make sure they ease arrow heads/ arbalest/ballistae down slowly on the ground.

Also, geometry of buildings is a non factor as long as you have towers and bunkers. Ballistae will be on towers to minimize the air time of projectiles. Even the mages need not expend too much energy. I primarily see them supporting the archers by making sure all projectiles hit their mark. So we can have like 10 - 20 archers and 2- 3 makes in each tower, and mages simply nudge the trajectory. Once the thick skin of any airborne creature is pierced, just throw a few lightning / fireballs at the shaft. That should cook the soft tissue, which then renders them less maneuverable.

In all likelihood though since we already established good line of sight earlier, we can tackle most before they reach the city.

Answer 3

It is going to be hard.

Have you ever watched those grainy WWII documentaries, showing you clouds of exploding flak (anti-aircraft ammunition) that seem to render the skies unsurvivable for enemy bombers? Well, post-war analysis showed that even in the most heavily defended areas, employing the newest technology then available, over 90% of bombers safely reached their targets. And this, in the context of high caliber machine-guns and cannons going against aluminium-skinned fliers.

You can imagine how effective archers and arbalists will be against nearly impervious dragon skin. Your mechanics can probably build spring-loaded ballistas with steel pikes as projectiles, but again, aiming them while fire is literally coming down upon you is bound to be challenging.

No, this will likely require a more high-powered approach. In theory, you could hire a guild of mages to protect you, but mages have the disadvantage of wearing flammable robes and of being rather squishy beings, when compared to dragons of similar magical ability.

Which finally brings me to the correct way of warding off dragon attacks. Since dragons are acquisitive, highly intelligent beings, the best way to ward off dragon attacks is to pay them off. While rampaging a city is undoubtedly satisfying, it is not entirely risk-free, whereas sitting in your cave as shipments of gold (and virgins?) are being delivered is a lot safer. The richest cities can go one step further, and hire certain nearby dragons for air defence purposes.

Let there be henceforth known to all, mighty and low, that the High City of Aaru is protected from attacks from the air by the glorious and powerful dragon Seugird'o'Rronairda. All who will dare raise fang, claw or flame against the city will face the fiery wrath of Seugird and all his allies.

Answer 4

There are two different types of flying attackers: bombers and melee attackers.

Melee attackers want to fly past your city's walls and attack your vulnerable civilians. If you're worried about this happening, you need to build each building as its own fortress: barred windows, barred doors, reinforced walls. Any building that gets attacked needs to hold out until the town guard can show up to drive the attackers off. Having lots of archers will also be really helpful.

Bombers would be large creatures -- maybe dragons, maybe airships -- dropping boulders or Greek fire on your city. Bombers can fly higher than your archers can shoot, and even heavier artillery will be really hard to hit them with.

One option against bombers might be to just put up with them. Your buildings are well-built and the boulders aren't as deadly as WWII bombs; it would take quite a lot of really committed bombing to seriously damage your city. In the meantime your ground forces can be attacking the place that's sending the bombers.

If putting up with them isn't an option, we need to talk about large-scale magic. Throwing fireballs at each individual bomber is not an option, but maybe your wizard can cloak the ground in fog so that the bombers can't find targets. With a bit more magic, maybe your city can make itself a no-fly zone: hurricane-force winds, or strengthened gravity, or simply a no-magic zone above the city to disrupt the magic dragons use to fly. Any of these options could be permanent or temporary.

Answer 5

Generally, you want a multi-tiered air defense network, consisting of several layers: area-defense interceptors, point-defense interceptors, long-range air defense, medium range air defense, and short-range air defense.

Area-defense interceptors would be flying combatants with extremely long endurance. They would be on constant patrol against airborne threats, directed by ground observers through whatever magical/technological means possible. Their job is to the first ones to engage the hostile force, as far away from the settlements as possible, and wear down their numbers and morale.

Point-dense interceptors would consist of low-endurance, but rapid fliers. They would remain on the ground until they are notified of an enemy raid, and then rapidly take to the air, and with the aid of ground directors, find and engage the enemy, preferably with the assistance of long-range surface-based defenses.

Long-ranged surface defenses would engage the intruders at as long a range as possible, preferably beyond visual range with magic or enchanted projectiles. Their job is to not to cause massive casualties, but to break up formations and organizations. It's hard to remain in formation or communicate with your comrades when magical flak is exploding around you or you are constantly trying to dodge the magical equivalent of a missile lock.

Medium-ranged surface defenses would engage the intruders at a slightly shorter range. Their job would be to upset the attackers enough so that, after being thoroughly roughed up by the long-range AA, would give up on the mission and turn back. They would most likely consist of converted siege engines, such as ballistas, or magic.

Finally, we have short-ranged AA. They would be either magicians with a very short casting time, or archers because of their volume of fire. They would be placed near places of interest, such as palaces, keeps, storehouses, etc. to put devastating firepower into anything that comes close enough to be exchanging blows with them. Unlike the previous two, the probability of either actually killing or mission killing the attackers would be very high at close quarters.

Now, this system would need a good command and control system. Invest a lot in magicians with quick communication abilities and scrying. The sooner the enemy could be detected, the sooner they could be engaged, and the more likely they would be turned back or destroyed.

Answer 6

Let's draw on the works of John Norman, creator of the Gor universe, which has exactly that and without the magic.
In his world there are swarms of airborn cavalry and raiders, human beings flying giant birds of prey and armed with swords, spears, and crossbows, plus lasso and bolo style devices to capture people (usually women to be carried off as slaves).
Cities employ archers on their walls, flying patrols of their own to intercept raiders, and giant nets of thin metal wire strung between towers over the city to deter the raiders and prevent them from landing (the raiders can carry a number of troops holding on to rope ladders to insert into the target city).

These same birds are also used for high value cargo and messenging services, so the netting is only put in place in times of war.
Of course the attacking power may try to cut the nets using hooks and other devices wielded by their raiders.

Answer 7

The hardest threat is the classic fire breathing dragon The most dangerous characteristics of the dragon in descending order are Flight Armored body Fire breathing powerful bite claws

A prepared town can drop dragons without any magic or hand waveium

Take cover and pull its wings

The alarms sound all the civilians hid in their basements archers duck into stone towers and the dragon breaths fire overhead. As the dragon passes by the archers aim at the massive unarmored wings of the dragon with large barbed arrows to rip up the wings. You can even attack ropes to the arrows so you can tare them out once the hit. Its mean but the dragon is trying to kill you. After a few rounds of this the dragon will have to little wing surface area to stay airborn this brings it crashing down and will prevent it from escaping.

Wound it from a distance

A grounded dragon can be outranged by ballista and powerful crossbows. Normally it is flying to fast to hit with powerful artillery but now its slower. You keep the ballista hidden in towers during the first phase now wheel them out and start wounding the dragon, this will bleed it and slow it down. Have fast brave mounted troops with spears and javelins harass and distract it.

Finnish it

Move infantry with very strong pikes and heavy insulated iron shields to slow and trap the dragon, keep wounding it till you can finish it off.

As a plus once you do it the first time you have dragon hide which is fireproof that you can use the next time you fight one.

Answer 8

Perhaps a focus should be 'what can the aerial attackers do and how would they do it?

Dropping rocks or firing arrows down onto a city isn't really much of a threat unless there are a very great many enemies.

The danger of aerial attacks in a fantasy setting one would think to be the ability to perform 'surgical strikes' but those surgical strikes needs b directed at predictable targets, and if a target can be predicted, defenses can be prepared.

firearms may be primitive, but a swooping dragon getting hit in the face with a bombard full of 'buckshot' isn't going to be a happy dragon.

ballistae don't need to hit the enemy to hurt them, they can be firing with the intent of closing angles of attack and/or trailing ropes from one defensive tower or tall building to another. aerial attackers give up many of their advantages when they choose to attack an enclosed space, unless the'yre kingfishers or some such, hovering isn't really practical for most winged creatures and flight lanes predicted.

The parallels drawn with ww2 bombing raids don't really make any sense, fantasy flyers don't drop thousands of tons of explosives from 10's of thousands of feet in the air.

Who killed Smaug again?

etc.

Answer 9

A city would have it's normal defenses, along with anti-air turrets/scouting posts planted on its walls. Inside the city would have sporadic anti-air turrets. If bombing is an issue, there would be bomb shelters.

The city would train or ally with friendly fliers to deal with enemy fliers.