The Brass Medallion No One Could Explain

I found it in a dusty wooden box hidden behind a false panel in my grandfather’s attic.

At first glance, it looked like an old brass badge—heavy, tarnished, and covered in strange markings. Around the center were dozens of tiny numbers arranged in a circle. The letters had worn away with time, but one detail stood out immediately:

There was a small hole in the middle, as if something once turned inside it.