(Forgotten Realms)
Menzoberranzan is a drow city in the vast underground realm of Underdark in Faerûn.
Geographically, it is located under the river Surbrin, north of the Evermoors, placing it somewhere between the Spine of the World (a small north/south direction reach of the mountain range, most notable location in that area is the Mithral Hall) and the Moonwood.
The city itself is a large cave of approximately two and half miles in diameter. The cave is adorned by many interesting buildings and structures, mostly built of stone, and many structures are built into the stalagmites. The whole area is carefully fashioned into something very beautiful and intricate. While the drow are known as cruel and evil race, they haven't lost the skills and appreciation of art and architecture. Near the center of the cave is Narbondel, a tall rock that is used as a magical clock.
Menzoberranzan has population of roughly 32000, a majority (~20000) of them are drow but the count includes also a whole bunch of slaves of various races (mostly goblinoids), and who knows what the count would be if all kobolds and other related catapult fodder would be counted! And let us not even think of counting all of the spiders!
The city is divided to several specific districts, each with their own variations and levels of glory. They range from noble and splendorous (Que'ellarz'orl and Narbondellyn of the nobles and wealthy people, and Tier Breche, the academy area) to less splendorous (West Wall) and quite okay (Manyfolk, the common people's district, and the Bazaar), to wretched (Eastmyr, the poor people's quarters, and The Braeryn, the slums, known affectionately as "the stenchstreets"). Finally, there's the Donigarten district around the lake of same name where the food is grown and herded (the lake has an island on which rothes are herded).
The society of Menzoberranzan is, indeed, an archetypical example of a drow society - and quite Orwellian too. Everything is all about being as lethal and backstabbing as possible under the disguise of order and law.
The society is efficient and the weak are not tolerated. The women are considered superior to men, and are the only ones that are allowed to become priestesses of Lolth, the Spider Queen. (Lolth is officially the only goddess worshipped in the city and non-worshipping is a crime - worshippers of other religions must either shut up and play along, or hide.) The men of the noble houses have two positions to fill, either warriors or magicians, but even the most talented ones usually cannot raise above women in rank. The most important source of warriors are the noble houses, but common people are also known to become full-time soldiers, if they can't find a role on the civilian sector - lowly commoners with nothing to do often end up getting sacrificed. For the less honorable and doomed people, there's always the opportunity to join Bregan D'Aerthe, a mysterious but successful group of mercenaries.
For the training of these three major professions, Menzoberranzan has the Academy, known as Tier Breche, divided in Melee-Magthere (warrior school), Sorcere (magic school) and Arach-Tinilith (cleric school). Each young drow of the houses spends time in each of them, though most of the time in only one of them, to focus on their own area. There are also older students and experts shining their skills.
The society is roughly divided in two major sections, the nobles and the commoners. There's also the outcasts who try to blend among the others.
The society is ruled, if it can be called ruling, the houses. There are various families / houses that are lead by the matron mothers and their daughters, and run practically by the powerful people under them. The council, of which the eight most powerful houses are members of, has the power over most of the city. As a result, most lesser houses fight the more powerful houses to climb in the ranks, and more powerful houses fight to keep what they've claimed and eliminate competition.
By law, an attack against a noble house or an individual noble is punishable - the defendant house can ask the Academy for appropriate punishment. But, if the attacker is competent enough to kill all nobles in that house, there's no one to ask for the punishment. The attacking clan absorbs material assets, army and slaves under the house's rule, and society as a whole then completely forgets the destroyed house. Whoever is weaker just does not exist, and as far as everyone is concerned, never did. Attacks of this kind are fairly frequent, but not always completely successful.
In recent history, the worst thing to happen in Menzoberranzan was the disastrously failed attack to the Mithrall Hall in end of 1350s. The attack was a total military disaster. At the time, very little thought was spent on what will happen in case of failure. The attack led to deaths and disappearances of various various important people, including matron mothers of several ruling houses (most important being, of course Matriarch Baenre, who was the unquestioned leader of the city for centuries). For a while, the town was in complete chaos, during which things like worshippers of Other Drow Deities (like Vhaeraun and Eilistraee) almost crawled from under the rocks they were hiding. Yet, these days, things are almost like they used to be. More or less. Give or take.
The city is often very hostile towards visitors, particularly those from the surface, but there still are some merchants who trade a lot of typical drow stuff, like poisons, mushrooms, and riding lizards.
Oh, weird, I got this far and did not even mention this was Drizzt Do'Urden's birthplace. I guess I am getting old.
Sources:
Forgotten Realms Campaign Setting
Quite a few works by R.A. Salvatore (most notably "Homeland")
http://www.geocities.com/Area51/Labyrinth/5425/menzo.html
There's also a computer game with same title (and setting), from SSI (1994?), a 3D CRPG similar to the earlier Ravenloft. (I haven't played this; anyone want to node it?)