This is a fairly small but densely populated basin. It is not considered a major basin by most of the planet. Many in the Highlands have never heard of it. It has none of the largest cities on the planet, but there are nine of over five million, and too many of over one million to mark. There are some interesting and varied landscapes and some unique cultures.
The map is 3600 miles north to south and 3400 east to west. This would be a lot of area if the Shimparan Waste didn't take up such a large part of it.
The early history of this basin is mostly conjecture. There was no writing in the area until modern times. A glideway went thru the area in the Energy Age but seldom made a stop here. The land it passed thru was just about uninhabited at the time.
The ancient peoples of Zil were a tribal people much like the indigenous population of the Trenst basin. They are small and dark and were suspected of being related to the Fmak in ancient times. Genetic analysis shows them to be more closely related to the inhabitants of the Yondure basin, with the natives of Trenst being the next largest component of their ancestry.
In prehistoric times there were no large settlements. There were crowded tribes of hunter-gathers in the central parts of the basin who lived a life that hadn't changed in twenty thousand years. Each band belonged to one tribe or 'totem.' The tribal totem was usually a stylized drawing of an animal or plant that was important in their lives. Many lived on semi-domesticated species in the chuff class, and/or lorisaurs that they kept in trees. Villages cleared no-mans-lands between them to restrain their herds and mark boundaries with a village of a different totem.
As far as is known, the custom of raiding each others camps, villages or other settlements for women and other booty goes back to the first settlement, and each totem has been building up grudges against the other all this time. Anthropologists from civilizations from The Realm till the days of the Instinct have sat at bonfires listening to old men chanting memorized sequences of deeds to be avenged.
The fact that they raided each other's women was the only thing that kept the different totems together all over the basin. Few of Zil ventured as far down the basin as the glideway in the Energy Age. Energy Age anthropologists also visited Zil, as did some from the Kassikan during the time of the Roman Empire. They saw the same culture and little more is known.
The area was still tribal when the peace plague reached the area. It brought more promiscuity to the basin and its culture, but not a lot more peace. Less violence was done against persons, more against property of the other totem. Youth did not reach this area until it was contagious, and then it spread it's way across via contagion with most people unaware of what was happening or why. Most people continued to live the same lives as they were, and most importantly, continued to have children at the same rate. The sterility plague reached Zil long after eternal youth did and the population ballooned. Starvation was a threat from then until fairly recently.
While Earth's year had three digits, ad., the Zil basin began to come out of the neolithic and take some features of more advanced societies. They established trade routes to Trenst, Vesh and Borlunth, using pack animal caravans. The first true cities appeared, the toilet came into use and deliberate agriculture became common.
The totem system adapted and totem halls were built. Full-time cooks appeared and the custom of eating at the totem hall took the place of eating at the camp firepit that had been the norm in the past. By 500ad. the peace plague had finally made some difference in the amount of inter-totem violence, so a totem could invest in a permanent structure with some confidence it wouldn't be burned in a raid in the next few weeks.
It is also mentioned by all the anthropologists from all the different civilizations that explored here, that the women had a high degree of autonomy to start with. By their code of conduct, any woman of the totem was common property of the totem. All that meant in practice was she was in trouble if she went to someone outside the totem. High status males within the totem could further restrict an individual woman's mating list if they desired. Their favorite ones were so restricted. By the time Rome had fallen, those restrictions had also fallen to the peace plague. The women of the basin have been considered to be a little more social than average ever since.
The Instinct didn't change the culture very much. All totem feuding had been via property damage for centuries, the Instinct changed the tactics a little. But soon after the Instinct an event happened that changed the basin even more, and that was the Janek migration.
During the the entire forties (421bc. - 959ad.), the Janek Nation attempted to remain a nation state on a voluntary basis. During that time they were able to get enough of the population of their territory to buy into the idea to function. At the time it was a California-sized region northwest of Knidola. After the Instinct, they were less successful keeping their valley clear of non-members, and their community began to break down.
Instead of passing from existence, a charismatic leader persuaded the whole nation to pick up and move to the Ydlontrostl basin, an extremely distant land that was only recently opening for settlement. The caravan took years to pass any given point. It took the average person ten local years to get to Zil. At that time the southern end of the basin was even more thinly settled than it is today. Those on the migration were exhausted and bored, their wagons and shoes were worn out, their kedas were bored. Most of them understood that they had only come one fifth of their journey. Charismatic leader or not, over a million of them did not go on.
Their effect on the society of Zil was profound. The Janek's were a civilized and ordered people. They were used to modern conveniences, and had more goods with them on their migration than most of the locals did at the time. With this constant beacon of change in their midst, the old society finally tipped. Totems lost much of their influence unless they evolved into business organizations. Over large parts of the basin floor, large numbers of people stopped going to the totem hall for their meals and began to set up kitchens of their own. The central Zil basin began to look a lot more like the Trenst basin, especially once data service began.
Those who wanted to preserve the traditional culture either moved to the Eastern Pinnacles, North Zil or the Traguzars. Each of those areas preserves some vestige of the old culture today, but only the Eastern Pinnacles still preserves the totem animosities.
Over most of the central parts of the basin today, one would think it is a steamier version of the Trenst basin. The music, clothing and cuisine of Trenst has taken over the basin today. Data service and being in the same time zone makes this area fertile for Trent's media companies, and they totally dominate the area.
Of the old culture, the only thing that remains is the clothing, a long rectangle of cloth with a neck hole cut in it that is laced up the sides. About a third of the population wear them at some time of the week. In the remote areas, two thirds of the population still wear them. Most today wear a wrapskirt or clout, or nothing at all because of the heat.
The largest city is Venblawk, but it differs from the other cities of the basin only in size. The cities are poor and lack any more cultural opportunities than the countryside. There is data service in all of them, but there is no wireless service anywhere in the basin. There are no energy resources for industry, so little is manufactured other than necessities. There are no tubeways in the basin and relatively few streetcars. There are traffic jams of farm wagons on the roads leading into and out of the cities.
The totems still run almost all pubic dining halls. There are just about no other sit-down restaurants in the basin. In the cities there will be five to fifty totems represented in a dining hall and they will each have a different meal. You can chose any totem today in the central basin, North Zil and the Traguzars. Most entertainment will be in these totem halls and most of the time it is a vid screen. There is some music and a lot of people will sing along.
Most of the time you can meet someone for the sleep at these dining halls. Over most of the basin it is not a problem to do so, but outside the central parts of the basin you should make sure your partner understands this is just a casual encounter or she could think there is more to it. She may be cute and sexy enough that you won't mind staying with her awhile, but she may want you to take her away from the region.
One should be careful in the Eastern Pinnacles however because the tribes in that area have retained almost all of the ancient culture, even though they have acquired some modern conveniences such as plumbing. Social pressure continues to keep chiefs in charge, and raids between villages are still common. Social pressure continues to keep women property of the totem and if you have an unapproved encounter with one, she may have no choice but to leave the village. You may find all your possessions destroyed and no food, water or shelter available until you are well away.
In general, in most of the settled areas, the most noticeable thing about the climate is the heat. On winter Dawnsleeps it's not hot, but Afternoondays in most parts of the basin are sweaty affairs of wiping the brow and looking for shade and cool drinks.
The central parts of the basin also look a lot like the Trenst basin. The vegetation is lush, huge clawleaves shade tiny homes and fields, flowering vines smother every fence, slow brooks choked with growth laze about the flat and steamy countryside. Everything moves at a slower pace. The smell of damp ground and old flowers pervades the air. Larorlie is everywhere but the climate is generally not seasonal enough for a concentrated bloom, but the air is thick and close enough that one often gets a buzz from the blooms.
North Zil is hot enough for hotbloods, and difficult for those with a body temperature less than 138F to survive. It can get to be over 120F (49C) and humid on Afternoondays. That is worse than it sounds because the air three miles below sea level holds more heat. Hangleaf and clawleaf jungles grow thick and the narrow, deep basin makes the weather unpredictable.
In the very far north the Zil River passes thru a spectacular canyon on it's way down into the swamp of hell. It is thought that there was once a time when the Karedarzin River took this route and helped erode the canyon. On the rim of the canyon, temperatures are bearable, but at the bottom temperatures regularly exceed 140F.
West Zil and the Traguzars are a little cooler. The Traguzars have the most pleasant climate in the basin, but most geographers consider that area to be a separate basin. In those regions it is also not as humid and the vegetation is a little more open. West Zil is not as deep and narrow an area as North Zil, but still the weather is unpredictable, and frequent droughts keep the population low.
The Eastern Pinnacles are higher in altitude and have a seasonal highland climate. Afternoondays can be as hot as the remainder of the basin in the summer, but the dark is quite cool in the summer, cold in the winter and snow is likely. The area has spectacular scenery. For seven hundred miles along the escarpment there are fantastic rock formations, caves, waterfalls and underground rivers. Villages often perch on rock spires connected to the land by draw bridges.
The good news about the Zil basin is that there is little dangerous wildlife unless you count the Traguzars as part of this basin. There are coriscamp in the eastern pinnacles and some blike (a carnivorous chuff) in the Zil delta, but you can't survive the heat there anyway.