To the South of Thyra, there is an area that has been permanently walled off. Even most of the tunnels and passages of Below end just before they reach this area.
Now simply called The Quarantine Zone, this was the area of the city that was hit the hardest during the War. The cost of repair being deemed too high, the whole place was simply cordoned off.
There is, however, an issue.
The Night fell in a roughly West/East trajectory. Upon impact, the QZ was in the same line as the impact trajectory. This is the area with one of the highest concentration of Passages known. Only 2 are known to be open (onto seemingly uninhabited worlds). Also, it is known that there is a similar area of Below beneath the surface, cut off from the rest of the network of tunnels.
Tales abound of riches and treasure behind every stone in the QZ. The Ministerium doesn't care too much about scavengers, although the Yellowstripes maintain a nominal patrol of the wall that isolates the area.