2 Euros Steam engine for draining mines

Slovakia's commemorative €2 issues have consistently highlighted domestic technological and industrial history, and this piece marks the steam-powered drainage pump developed by Jozef Karol Hell in the 1740s at the Banská Štiavnica silver mines. Hell's machine — built decades before Watt's improvements to the steam engine — was among the earliest mechanically sophisticated mine-drainage systems in Europe, and the Banská Štiavnica mining academy later became the first technical university of its kind on the continent.

The mines it served had been flooding badly enough to threaten closure entirely.