Every undercity is different.
Topography changes from place to place and there are many element of the local undercity that exist simply because of businesses in the area. (My home city is Lexington Kentucky and there are multiple universities with underground areas near downtown as well as a mining operation that has been a going concern longer than I have been alive.
Many times the lay of the land is manipulable by various factions of supernatural creatures that prefer to lair underground. (I am thinking mostly of Nosferatu vampires and certain types of Beast characters.) But just because this is where the monster hang their hats, is no reason to suspect that regular people can't or won't stumble across these sorts of areas in the course of their lives.
So, With that in mind I have put together a number of common elements that one is likely to see in underground urban areas.
The Tangles:
Undercities can be dangerous places to live. Cranky fellow nosferatus are usually the least of your worries. Some underground denizens take exception to an invasion of their territory and there is the slight possibility that an aboveground assailant will give chase to a nosferatu into his home ground. That's why Nosferatu build Tangles.
A tangle is an area within a Nosferatu undercity that has been turned into a deliberate labyrinth. Often a Tangle requires a certain amount of 3-dimensional traverse. Moving about up and down, and from side to side. (Many tangles also have small holes enabling small animals and kindred who can assume animal form to move across them more directly.) The center of a Tangle is often a form of Panic Room with bulkhead doors. Inside, one can find the following:
1) A selection of mauls and fire-axes
2) A phone with a hard line and a Cat 5 cable jack. The phones direct dial buttons are to other places in the undercity.
3) 1 shotgun and a box of ammo. The shotgun has the words "Watch out for Methane Dumbass!" painted on it's barrel.
4) A selection of levers that can cause a number of problems for attackers. Places having a lot water to work with use that to it's advantage, often causing a passage to lock off and then flood. Other levers might unleash a dead-fall or drop a manhole cover down on a climbing assailant. Pit traps dropping a kindred onto wooden stakes are another favorite. A handy key is painted on the wall above the control box.
5) CCTV for keeping an eye on the attackers outside and seeing if your rescuers have come.
The Howling Gallery
Engineered by a Nosferatu named Linus Janisek, a German national who emigrated to America to be part of the arts community here, The Gallery is blessed with unusually warm acoustics. Linus, seeking to exploit that unusual aspect of the place, asked for help with routing pipes through the top end of the cavern. As a result of numerous, water, sewage,and HVAC pipes being routed through here, there is a low continuous moan through the gallery at all times. It has been speculated that the gallery has the potential to be a Geomantic Nexus of some sort, but nobody seems to know what sort.
The Gallery has stolen power and light provided by a number of stolen stage lighting devices, (There is a closet full of backup equipment, gobos and gells, but much of that stuff hasn't been monkeyed with in ages. The pipes and the ceiling of the room are kept scrupulously patched and dry, so that the room stays that way as well. The lights can be moved around on the pipes a bit offering some variety. The floor of Gallery is usually home to artworks by and for Nosferatu. Adding to the atmosphere here in the gallery is a Theremin which stands in the center of the cavern. Certain of the lower frequencies have been known to make the paintings and sculpture vibrate. (And on at least one memorable occasion cause a frenzy)
Linus's Sepulcher is nearby, and it's said that when he was in residence, he could hear anything that is said in the gallery itself. It's unknown whether Linus was a victim of the Revenant Princes purge or whether he's just away or in torpor somewhere.He has been known to travel to purchase new artworks for the gallery. It is rumored that he's Invictus and a member of the Angels besides.
The Artworks Include:
1) A series of framed photographs of child kindred entitled "Predators"
2) A medieval style tapestry like those found in Bayeaux, This one seemingly depicts some long drawn out conflict between kindred factions in the south of France. The conflict seems to culminate in a mass diablerie.
3) A large marble nude male wearing a closed face roman style helmet and carrying a spear. Possibly stolen from a Ventrue descendant. Nobody's talking about it.
4) A large wooden totem of an owl stolen from a burial mound museum in Wickliffe Kentucky. Rumor is that the Indian tribe that worshipped this totem exterminated themselves in a mass ritual suicide. Kindred who look upon the statue often report a feeling of being both fascinated and uneasy.
5) a modern art piece which is a flat pane of glass enclosing some red liquid which undulates ceaselessly. It's essentially a lava lamp, and while not supernatural at all, tends to make kindred viewers hungry.
6) An open exhibition block that apparently was home to a permanent exhibit that has, since Linus's departure, been stolen. The area above the block remains a constant 17 degrees colder than the rest of the room and there is a strange scent of lilacs.
7) A portrait of the toreador Primogen reclining nude upon a chaise lounge. Painted by Linus himself.
The Devil's Door(s)
Sometimes covering entries into the undercity is a tricky situation. Most kindred can enter the Main Hall and venture outwards from there. Others know they can usually get in via an outflow pipe near the river or bay, or pop open a manhole and dodge the utility worker guys. But some doors to the outside world are too convenient to leave unguarded. And while guard duty is a good way to work off debts, it's not fun and no good during the day anyway. As a result, some Dracul types have devised a means of using spoiling to treat certain doors in the sub-sub basement of buildings. Such doors are often hard to perceive in the first place. Some being hidden by powerful obfuscate, But should a mortal manage to see them or blunder into them, they are subjected to the second line of defense, this being distilled essence of spoiling coupled with nightmare. Filled with an irrational fear of the door in question, many go running in the opposite direction. There have even been instances of humans falling over dead from heart failure.
The Garden
A long oval cavern, the Garden has only two entries, both are solid iron doors with a time lock on them. The room has a series of cunningly crafted pipes stretching into the city over head, all of them stretching high into the roof tops of the buildings overhead. Each is a form of periscope that links below to a cunning series of mirrors and lenses below that manage to give a full daily sunlight bath to the botanical garden below. Water is provided by various water pipes and a storm drain pipe or two. A makeshift aqueduct makes certain that the water is evenly distributed. The Garden was created by a Nosferatu named Green Jean, who has long since met her death. Her childer tend the place now in her memory. The plants are ghoul plants, and produce lacrima in copious amounts. Additionally, there are carnivorous plants being grown here in such size that one of the Pitcher Plants requires a house cat to feed it, about once a month. Grean Jean's childer still keep an eye on the area and grow extremely potent poisons, hallucinogenic mushrooms, peyote, ayahuasca, and marijuana. The Garden is also considered neutral territory, mainly by dint of the fact that violence tends to agitate the plants and they MIGHT attack. As a result, when a sit-down between factions or kingdoms is called for, this is the spot for those sorts of meetings.
The Torture Suite
The first one was built by a Mekhet named Bardolph. It features a dentists chair, with welded on manacles. A pipe stretches into the over city and collects light from the sun directing it downward via long stands of lucite. (Bardolph is said to have designed the lighting system of the Garden as well.) The lucite strands are coiled and then covered all the way down to the tip. The questioner often dons a welders mask, gloves and other protective gear, and then pulls down the tool from a reel overhead. He is then able to uncap the end and in effect write on the kindred flesh with a needle of sunlight. naturally, the gauges of lucite go up, to cause more pain. There is a cannibalized firehose connected to an outflow pipe of freezing cold water to put out the kindred, should he begin to burn freely. Other more pedestrian torture devices line the walls here as well. A car battery with alligator clips also sits on a dolly. (Although by this point it's long dead.
Dodson's Flush:
It's unclear as to whether Dodson was the Nosferatu who built it, or was the first Nosferatu executed by it.
The Flush is essentially a larger than man-sized outflow pipe for storm-drain pressure release. It is situated at a high point in the City's topography and terminates down by the riverside somewhere. When a Nosferatu, or any other intruder in the community has transgressed, That transgressor is usually bound in anchor chain, dumped into the outflow tub and then the release lever is pulled. The outflow is at least a mile long and the transgressor is usually going over 45 miles an hour when he or she is ejected, usually into full daylight. Even if, it's not daytime outside when you land, it's usually a pretty good idea not to go back to the undercity until you've mended your fences.
Phlegethon
While most of the various necropoli sport Caldarium of their own, This one is the largest and most popular, resembling nothing so much as a Plato's Retreat for Nosferatu. The Caldera are large and warmed by number of routed hot water pipes, Legend has it that the disco ball was stolen from Studio 54 one night, and that it seems to have a sort of disinhibiting effect on those who enter the club and partake of the waters. While no one is sure if there is something unusual going on, like some sort of spiritual mojo, it is well known that the Necropoli where it is located is one of the most friendly and close knit in the undercity. It may be something on par with the weird sex club found in the movie "Eyes Wide Shut" Seems like there might be an unseemly amount of blood sharing going on between kindred down there. Ew.
The vast corpulent owner of the place is rumored to be one of the rare Crones in the undercity and a devotee of the Second Descent. He may also be older than he lets on, but rarely presses any sort of political issue as long as it doesn't crab his personal decadent pleasures.
Dis-Mart
Named for the Iron City of Dis, this area is considered to be a large scale persian bazarr style market. The fact that it's split up between 6 city blocks worth of underground area means that one can go there and not find the same wares on sale each time. It's rumored if one knows the rights words to say, one can find a slave auction or a blood market. Trucks get hijacked all the time, and a percentage of those jackings are the work of Nos, who sell off the wares here. It's also rumored that Green Jean's childer sell off some of the more hallucinatory mushrooms that grow in the garden here.If it's illicit, odds are good you can get it here. Dis-mart is even fairly accessible to kindred of the surface as it is near the Capital, and is near the surface as well. It's even rumored that a certain manhole on North Dansky street leads straight down to it, But the rumors differ on which one it might be. Not to mention how it's never been seen by mortals working for the utility company. The one thing that is kind of a drag about the Dis-mart is that it is so split up in the catacombs it inhabits, that one can get turned around if one is not careful. This is of course the one thing that prevents open warfare from breaking out here as well.
St Judes
A gathering place for the faithful of the undercity, Crones, not being common here, tend to go aboveground to revere their goddess, but some of the undercity faithful haven't been above ground in a long time, Father Vitus is that rarest of creatures in the sanctified, an elder AND a true ecumenist. He is a biblical scholar and probably would be an archbishop anywhere else, but he is proud to offer spiritual guidance and comfort here. His church is a somewhat cramped affair, but for all of that, offers the sort of squalid opulence that one would expect in a kindred house of worship. Most of the mouldy furnishings have been scavenged or stolen from churches all over town. The place smells of mouldy wood, and velvet, and candle wax. In addition, St. Judes also offers outreach to homeless humans in terms of medical care, food banks, and occasional shelter, usually in exchange for just a little blood. It doesn't even have to be yours.
The Nerve Center
Nosferatu in the undercity take the whole idea of keeping an eye and a camera on things deadly seriously. While the Nerve center rarely sports bleeding edge technology, it does have a tiny army of technologically adept Nosferatu, Mekhet, and ghouls of the same, that work very hard to piggy-back as many signals as they can manage into the screens and mainframes. Screens are often cued to flip every few seconds or so, allow the watchers to "Gloss" footage and take in vast amounts of material in a short amount of time. Not surprisingly, the Mekhet are best at it, but some ghouls can do it too. Meanwhile, the network of hackers both here and above ground hack and install backdoors into nearly every system in the municipal networks. Attempts to track these hacks back to the source inevitably run into the fact that the hackers are directly patched into a trunk line which services half of the city. By design, the Center is actually segregated from all of the undercity around it, and is only accessible via the freight elevator of an office building in alphabet city. The long corridor leading to the nerve center is covered in multiple claymores. It can also be flooded with nitrous oxide at the flick of a switch. Most of the kingdoms in the undercity need information from the Nerve Center, so they generally offer people to staff the place to pay off debts, but since many of the Undercity kingdoms are in some sort of low level struggle with one another, things can get tense in the Nerve Center Situation room.
The Arena:
A large open space with second level that goes all the way around and offers a prime place to witness any sort of duel that is going on down on the floor below. The doors into the Arena Floor have a magnetic lock that has a controller that is in the hands of a proctor for the challenge. (By tradition, someone chosen by the seconds of the duelers in question.)
When the arena is not in use for its intended purpose, it usually home to a massive half-pipe and an area of obstacles for practicing parkour.
