Persistent postural-perceptual dizziness (PPPD) is simultaneously one of the most common dizziness and vertigo disorders, the most prevalent form of chronic vestibular syndrome, the quintessential example of functional vertigo, and quite a mystery. Its mechanisms and pathophysiology are the subject of intense debate and research. The more we learn, the more accurate its definition as a functional pathology seems: a disorder not linked to structural abnormalities but characterized by persistent changes in certain brain functions. The crucial question is which brain functions change in PPPD and how they change. The purpose of the following lines is to delve into these questions. From a personal perspective as an author, I am convinced that the answers for these questions (or at least making the effort to find them) can not only contribute to understanding PPPD to provide new tools and alternatives for its diagnosis, management, and treatment, but also present PPPD as a unique opportunity (a model) for studying how the brain constructs its internal model of the spatial environment in which it moves. These functions of spatial cognition and navigation, as we will show, seem to be key in explaining PPPD. Furthermore, PPPD offers a chance to explore sensory functional neurological disorders of the brain beyond PPPD, spatial, or vestibular contexts.