The origin of Cosmic Rays (CR), more than 100 years after their discovery, is still considered a "century-old mystery". The reason for such a pessimistic assessment is that we do not know yet, despite the recent remarkable advances in CR studies, which source population(s) contribute to CR fluxes measured in the Earth's vicinity (local "CR fog"). Identifying the contributors to the local CR flux with known astronomical source populations is one of the highest priorities of the field. However, the CR studies cannot be reduced merely to this objective. The term "cosmic rays" has broader implications. After matter, radiation and magnetic fields, these relativistic particles constitute the fourth substance of the observable Universe. The localization, identification and exploration of physical conditions and processes in these CR factories, independent of their relative contributions to the "CR fog", is a fundamental issue in its own right. In this context, the Extreme Accelerators - perfectly designed by Nature machines accelerating particles with a rate close to the theoretical margin, in general, and their subclass, the so-called Galactic PeVatrons, in particular, are of special interest. I will discuss the recent progress in this area thanks to the (surprise) discovery of a large number of electron and proton PeVatrons in the Milky Way. Zoom link https://zoom.us/j/95485119455?pwd=WkhxWkNDVlhBcER4TTU2M001aEw0UT09