The hole in the fabric of the universe beside which Roland and his companions camp near Topeka, Kansas, is called a thinny. In Stephen King’s Dark Tower mythology, a thinny is a strange, unstable tear or thinning between levels of reality.
The scene occurs in The Dark Tower IV: Wizard and Glass, after the ka-tet arrives in a version of Topeka, Kansas, aboard Blaine the Mono. The location is not simply a physical cave or ordinary gap; it is a dangerous dimensional phenomenon that produces eerie effects and threatens the boundaries between worlds.
Thinnies are part of the series’ larger idea that reality is made of multiple levels connected to the Dark Tower. They can appear as places where the structure of existence has weakened, allowing unnatural forces or sensations to intrude. Roland has encountered another thinny earlier in his life, making the Topeka episode part of a recurring pattern rather than an isolated oddity.
The term is easy to confuse with an ordinary “break” or “hole,” but “thinny” is the specific name used in the novels.