15km deep

Deep underground, within a cavern, there was a giant city built into the walls and floor. The houses where dark and shaded with black and brown being the primary colours with a few greys mixed in. The city was shaped like a semi-circle with cave abodes on the two sides being of smaller size than the middle where there was a massive abode divided into ten sections and then 1 giant section in the middle as if the ten abodes where protecting the one in the middle while also being centred around the middle one. Within the middle abode, there was currently a meeting ongoing as 3 sets of people sat in a triangle. The heads of the three sects were sitting at the forefront, in a triangle with each other while each sects elders were sitting in a row behind their respective sect master, forming a weird double triangle.