Imperial Buildings
The Imperial Covilla
An Imperial Covilla is the standard living and working structure of the Empire. A Covilla usually has between three and nine stories and is built of stone or masonry using sturdy barrel arch and groin techniques. They tend to be quite large and often fill an entire city block. They almost always have a central forum open to the sky and flat roofs upon which there is a lush roof garden, almost always tended by one or more Wardens.
Covillas usually have skyports on every floor above the second, arranged around the outside so that drays, sedans, and landaus may arrive and depart. Personal carriages are commonly parked above the open central well, so that the owners may keep an eye on them. Covillas often have skywindows for comfort and in the current empire many even have an ethernet dropoff in the central forum.
The first and second floors of a covilla are dedicated to shops and storehouses, with the upper floors given over to homes and offices. A covilla can be the home of many hundreds or even thousands of people, or be inhabited by a single family with or without a staff of guards and servants.
The Tower
An Imperial Tower is an imposing structure built of heavy stone. Most towers also serve as water lifts, and thus have tall aqueducts marching away in various directions. The most modern towers may or may not be used to lift water, and many of the very newest are not even very tall. Older towers may reach one thousand feet or more in height, while a modern tower is rarely taller that three hundred feet.
Towers are industrial installations, and contain either a turning house, with circuits of fundaments writhing in the grip of gravity to provide mana and power to various dweomers, or the very most modern will contain a Well, a tap into the Plane of Power.
A Tower is often found in even a small city, and the turning house provides jobs and power for much of the cities industry, making weapons and armor for the Legions, Army and Watch, consumer goods for the citizens, and driving the protective charms and enchantments of the various temples that control the weather, warn of invasions, fend off plague, and the like. Near the border of a realm you might find a lone Tower atop a promontory containing a Well, and the Well is powering the Veil around the Realm or powering the Ley Lines across the entire realm.
The Imperial Fortress
The Legions, the Provincial Armies, and the Watch maintain innumerable fortifications and strongpoints everywhere the Empire goes. These range from sturdy square buildings of simple stone used as Watch posts, up through the large fortified bastions of the Armies, to the mighty Gate Houses of the Imperial Legions, all the way up to colossal bastions like Northgate Grimhold and Fuerholm Holdfast which guard the passages into the First Realm.
Smaller, local fortresses such as are used by the Watch and Armies are strongly fortified and occasionally reinforced by siegestone. They may house anywhere from a lone Watchman to an entire Provincial Army Complement, or even more. Imperial Fortresses tend to be larger, with even the smallest capable of housing a full Imperial Complement of some fifty thousand troopers. The 'standard' Imperial Fortresses are the massive Gatehouse, in which the Gates are kept. Gates are the fastest way to travel within a Realm, and as a result, they are massively guarded and carefully controlled by the Legions. Anyone may use a Gate, but it's expensive. Militarily, attack a Gatehouse Fortress means that you are attacking the entire Imperial Legions, and if the siege is not resolved quickly, at some point the doors will open and legion after legion of troopers will come marching out, having just arrived from far-distant points via the Gates.
Imperial Gatehouses have been lost in battle over the millenia, but it hasn't been frequent.
Ley Lines and Keystones
Ley Lines are usually laid in on Imperial Highways. A Ley Line is propagated by Keystones, large stone and crystal devices (twenty feet tall) what are usually embedded in the roadway every five miles. A Keystone may be empowered by a connection to a Well, or by a connection to another Keystone. While empowered, a Keystone provides buoyancy to all Ley Keels within range.
A carriage, from the smallest Broom to the largest Galleon, always has a keel. As long as the keel is empowered by a Manastone or a Ley Circle, and remains within a few miles of a Keystone, it floats!
Most roads have Keystones close enough together that you can fly a carriage anywhere within five miles of the road. Maximum altitude is five miles as well, although very few drovers get above a few thousand feet due to the peril of the Sky.
Cities usually have a network of Keystones buried in plazas, so that you can fly a carriage anywhere around a city with no problems. A single Keystone provides flight for a circle ten miles across. Seven Keystones can loft a circle twenty miles across. Nineteen Keystones can loft a circle thirty miles across, Thirty-seven Keystones can loft a circle forty miles across, etc.