Gewerkenegg Castle

Gewerkenegg Castle stands at the heart of Idrija, a small town in Slovenia's Goriška region, and was built not as a noble residence but as the administrative headquarters of the Idrija mercury mine — once one of the two largest mercury producers in the world. The castle's very name reflects its industrial origins: 'Gewerkenegg' derives from the German word for mining guild. Since 2012 it has formed part of the transnational UNESCO World Heritage Site 'Heritage of Mercury: Almadén and Idrija,' pairing it with its Spanish counterpart in a rare cross-border designation. Today it houses a branch of the Idrija City Museum, open daily until 18:00, with exhibits covering mining techniques, the daily lives of miners, and the environmental and human toll of centuries of mercury extraction.