Doom of the Drow
Menzoberranzan: Tier Breche
As of 1466 DR (Dalereckoning), Menzoberranzan continues to endure as the most powerful Drow city in the Underdark in the North. Surviving the Silence of Lolth, an assault by the combined forces of Duergar, Demons, and attacks by a shadowy league of assassins, the resiliency of a city born of the wicked Drow stays true as the cunning of Lolth herself.
Tier Breche, a small pocket cavern sitting higher than the rest of the city, as a name that was synonymous to the Academy of Menzoberranzan. In short, Tier Breche was also referred to as the Academy. Of this Academy there were three very different structures that housed the education of all core professions of the city: Arach-Tinilith (the school of priesthood to Lolth), Sorcere (the school of the arcane), and Melee-Magthere (the school of martial combat).
Carved from the stalagmites that composed many of the structures in the city, each school had a flavor to its design: Melee-Magthere was shaped like a pyramid and was located in the east of Tier Breche. Sorcere was composed of various spires that supported a tower, sitting to the west. And ultimately, Arach-Tinilith was shaped as a large spider, greatest in size at the northermost end of Tier Breche and housing the most students.
A long set of stone stairs connected Tier Breche to the rest of the city below, guarded by two graduates of Melee-Magthere by the twin pillars which flanked the entrance. Further defenses include magical wards which sounded loud alarms when breached, and two large spider statues that would animate in protection of the Academy.
A near century ago, duergar utilized an uncommonly known tunnel that connected Tier Breche to the lands beyond the city. This weakness was been given more attention since then.