10 Balkanów - Katowice Spodek

Katowice's local currency experiment launched in 2009 as a promotional initiative tied to the city's identity, with the Spodek arena — completed in 1971 after nearly a decade of construction — chosen as the defining symbol. The building's engineering was unconventional enough that Soviet-era structural consultants were brought in during design, with the suspended roof tension system drawing on principles used in radar dish construction.

The amber inclusion in the tombac blank is the unusual production detail here: physically embedding organic material into a struck coin requires resin stabilization and careful die pressure calibration to avoid fracture.