Gassner architecture is noted for its modular nature, utilitarian construction, and ultimate pragmatism. The flagship of the style was the Gassner Tower.
The Gassner Tower was built following the golden ratio, being 1.6 times as tall as it was square. This was accomplished by its modular structure, combining prefabricated boxes with readily available internal units. Unlike previous structures, the mechanical aspects of the building were built on the outside rather than being buried inside. All of the water, air, electrical, and other utilities were along a single outer wall. A cluster of Gassner towers would create mechanical 'alleys' where their utility sides all face each other.
A Gassner Tenement would be created by bunching several Gassner towers together to create massive block like structures. The tenement doesn't have an alley, but it's outer faces are covered with the mechanical elements. These tenements could efficiently house tens of thousands of people and begin to reach demi-arco dimensions before encountering structural failure issues.
A Gassner City would be created by building blocks of Gassner tenements together into regimented blocks. These blocks would then be 'plated' creating a second surface, with slum like undercities created almost instantly.
The Future was intended to be vertical slums. The Gassner cities would be linked together with magnetic rail lines, and the increasing populations would cluster together into denser and denser megacities.
The greatest problem the old cities faced was the increased cost of maintaining old buildings. Many were large, and the cost of tearing them down far exceeded the cost of maintaining them. Many of these antique buildings were simple entombed in Gassner towers or in the spaces between them. Tenements housed massive numbers of people, creating an equally massive underclass, a staggering strata of immigrants, the poor, the outcaste, the downtrodden, and those who were simply the ants in the colony.
The Gassner towers revitalized many urban areas. This success lead to further development, and a number of tenements were allowed to be built. New charter cities were planned, and there began an exodus. The old urban population centers were relocated to the new tenements, and as populations moved, more room was made for new construction. Thus, the Petroleum Era boomed on.
The New Age
The new cities grew at a staggering rate. Tenements were built over massive boulevards, with mezzanines creating open green space that wasn't given to transit purposes. The megacities grew, with the mezzanines growing closer and closer, until they merged. A few kept skyholes to allow natural light to fall into the tiers and districts below, but this was increasingly uncommon as the tenements increased in size and height. There was a trend that the higher levels were more opulent and expensive, and new construction would go ever upward. Each new level devalued the deck beneath it. Construction boomed.
The Gassner towers grew around the world, and there was no one nation with a great claim to them. Many second and third world nations built them as fervently as many old world nations did. Many of these had the advantage of not having urban cores that were hundreds or even thousands of years old. Those aged cities simply fell behind. New York was overshadowed by the massive New Nuyork, built a score of miles away from the original city site.
The new cities developed strata. The wealthy on top, the criminals on the bottom, and everyone else scattered between. The early and middle Petroleum Era need for mobility decreased, and the ubiquitous automobile was slowly overshadowed by intercity transit. Electric scooters, mobility systems, skates, and the rest became more popular than cars.
The Old Cities didn't die, the wealthy remained, and a 5th avenue penthouse overlooking Central Park was still considered prime real estate, and the new cities revealed themselves as increasingly poor, despite their massive size and population. The old money, the old influence remained in the old cities. The creation of the Nu-Cities was almost a godsend as it drained the 'riff-raff' out of the old cities. Living on the street in an old city was nightmarish compared to the relatively safe and comfortable if crushingly poor and oppressed lives in the the nu-cities.
The Birth of the MegaCities
The megacities were the hallmark of the Late Petroleum era and the Resource Wars. The global population surged to 8 billion, then 10 billion, then 12 billion. These megacities grew and swarmed. The Gassner cities packed together, undercities flourished, crime exploded, organized crime grew exponentially. Each megacity flexed its sociopolitical muscle, and through sheer size outweighed the states that surrounded them. Each of the world governments found themselves increasingly catering to the populations of the megacities. This saw the leading nations lean further towards socialism and progressiveness, while embracing militarism with great zeal.
The new cities all looked the same, the same buildings, the same patterns. This lead to a collective effort to make the cities different, unique. The various blocks and districts also sought to distinguish themselves. This lead to a re-emergence of neighborhood games, of civic mascots, and the rest. This was echoed in criminal gangs, and local industries.
The Megacity was laid out in a heavily planned manner. Tenements were raised not just as housing, but as foundations. After a certain number were completed, a second stage of construction would spring up from the top of them. The megacities were tiered like the hanging gardens of Babylon. The very center of the megacities would be dominated by a ziggurat like 'pile' of building. This was the central administrative sector, and could be as taller than most previous skyscrapers with a dramatically larger foot profile. Some of the truly massive megacities could even have a ziggurat complex at their heart.
The Death of the MegaCities
The Megacities were a cancer on the face of the planet. The amount of resources they required was exorbitant. They consumed obscene amounts of electricity and almost unfathomable quanities of water. Moving the consumer goods and food required by the city made them the focal point of the region they were in. Some states experienced regional famine and water shortages in the effort to keep the megacities supplied. When these resources looked to come up short, the governments were more than willing to use police, paramilitary forces, and eventually the military itself to take the food and other things that the cities required.
The St Louis Debacle saw the last tank offensive in US history. The old city of St Louis was being used as a collection hub for shipments of food and other goods to the megacities swarming on the east coast, and in the US midwest regions. This was seen as offensive to the residents as they had been faced with food rationing, and police searches of their homes to make sure that no one was hoarding goods, or participating in the local black market. The violence and destruction levies against the city saw further uprisings at other supply hub cities, and the megacities started feeling the constriction of their supply lines.
The megacities, with large dense populations, poor prospects, and weak education, were primed for violence. The very layout of the cities made holding them difficult. Police departments resorted to more and more extreme tactics and heavier gear. A megacity police department could easily have as much firepower as an actually military division. This access to weaponry combined with the structure of the city, and the volatile population was a bomb waiting to go off.
The New Nuyork police force consisted of eight divisions, and had a combined manpower of over 110,000 officers. This force had over a quarter million firearms, 1200 squad cars, 90 VTOL aircraft and helicopters, and 15 surface ships. During the worst of the New Nuyork riots, this police force was unable to take and hold ground against rioters, and were only able to make containment lines around the more affluent parts of the megacity.
The Resource Wars
The large hungry violent populations of the megacities pushed the Resource Wars over their demand for cheap consumer goods, conspicuous consumption, and cheap energy. This equal supply of men and women for the fight, and the demand for the fight pushed the governments and militaries of the world into increasingly violent confrontations. As fuel supplies dwindled, the previous style of fighting, with sweeping movements of tanks and combined air support was replaced with large infantry formations, heavily armed, and fighting like World War 1 soldiers.
Few cities in the west faced full war, but many of the megacities in Asia, Europe, and Africa were scourged by war. The massive armies would fight Stalingrad like campaigns to take and hold a city. Artillery rained down, the remaining aircraft dropped bombs, and millions of men and women were thrown into the meat grinders. Armored vehicles were abandoned as they were unable to survive in the urban canyons, and were unable to punch bodily through the buildings of the megacities.
The Rise of the Arcologies
The Arcology rose in defiance of the Gassner towers. While taller, they had less internal space, and couldn't hold the millions who inhabited the megacities. These often times beautiful and artistic megastructures were raised in the hearts of the old cities, build atop the vacated urban cores. Where the Gassners were resource sinks, the arcos were largely self sufficient. They generated their own electricity, recaptured and recycled their waste water, and had huge internal recycling programs. The wealthy lauded the towers as they moved into them, and the megacorps did the same, they were much easier to secure and protect. Meanwhile, the similar structures in the megacities demonstrated their vulnerability. An animosity grew between those who lived in the towers and the megacities. The towers, by virtue of their size, could often be seen from the new cities that were raised near the old. This was a constant reminder, the wealthy lived elsewhere, and that even the top floors of the megacities were no more important than the bottom of the arcos.
The End of the MegaCities
The Megacities required massive resources, and were highly dependent on grids, and infrastructure. When the grid collapsed, and the Hypernet shut down, there was an exodus from the cities that were not able to adapt. There were local and brushfire wars between the waning megacities, against each other, and against the arco cities. The Population Contraction saw the demand for the cheap real estate of the cities fall. Many of the cities were completely abandoned, left to decay.
There are few megacities more stark than New Cleveland. The megacity boomed during the Late Petroleum Era, and became an economic superstar for construction and distribution. As it's resources waned, the population supported finding the fields and supply centers of other megacities and taking them. This would spark the disastrous Midwest War. On one side, the nascent Republic of the Great Lakes, on the other, the Commonwealth of New England. This war saw the launching of the first battlemechs, and the wholesale destruction of both new and old Cleveland. New Cleveland was savaged with thermonuclear weapons, and old Cleveland was decimated by street to street fighting during the sixteen month long battle. A truce was brokered, and both forces retreated. New Cleveland, once home to over 5 million, was a vacant radioactive ruin, and Old Cleveland was abandoned as a ghost city.