The tajchy — artificial water reservoirs built to support the mining industry — are one of the most unusual features of the Banská Štiavnica landscape. Scattered across the Štiavnica Hills in a broad arc around the town, they were built between the sixteenth and eighteenth centuries as part of an ingenious hydraulic system designed to manage water levels in the mines. Today they look simply like pleasant mountain lakes, attracting hikers, swimmers, and picnickers who may not realize they are walking around a feat of early modern engineering.
The most accessible are within easy walking distance of the town center, and several have become popular recreation spots. The Počúvadlianske jezero and Vindšachta reservoirs are among the larger ones. For hikers, the network of trails connecting the reservoirs makes for a rewarding half-day walk through wooded hills with periodic views back over the old town.