The Township is the central area of the DLC and connects to everything and everywhere. It is the best level in the DLC for a myriad of reasons. It captures the decay and depravity of the Abyss perfectly, making the descent into the black void all the more powerful.
Not only that, but it has so many hidden nooks and areas that most players will walk past, all of which are intertwined in a way that is constantly surprising. The number of elevators and shortcuts is incredibly impressive.
The DLC focusses a lot more on bosses and enemies than it does areas, but Oolacile Township proves that even that shift in focus barely puts a dent in FromSoftware's level designs.