Idrija is a small town located in western Slovenia, known for its rich history and natural beauty. The town is situated in the Idrija Basin, surrounded by lush green hills and forests. Idrija is most famous for its mercury mine, which was one of the largest in the world and is now a UNESCO World Heritage Site. The town has a charming old town area with narrow cobblestone streets and historic buildings, including the 16th-century Gewerkenegg Castle and the Church of Mary on the Rock. Idrija is also known for its lace-making tradition, which has been practiced in the town for over 300 years. Visitors can learn about the history of lace-making at the Idrija Lace School and see demonstrations of this intricate craft.