Municipal Museum

The excellent Municipal Museum is housed in the enormous Gewerkenegg Castle on top of the hill to the west of Mestni trg. The collections, which deal with mercury, lace and local history, are exhibited in three wings centred on a courtyard. The rococo frescoes of plants, scrolls and columns framing the windows and arcades date from the 18th century.

Mercury (Hg) is the only metal that exists in a liquid state at room temperature. The silvery metal is extracted from the mercury ore - a bright-red mineral called cinnabar - by smelting at a high temperature. Mercury is a very heavy metal, much denser than iron, and in the castle's north wing, amid a jungle of minerals and fossils, is a large cauldron of mercury with an iron ball floating on the top.

Part of the ethnographical collection in this wing shows rooms in a typical miner's house at various times in history. A miner's job carried status, and they earned more than double the average wage in this part of Slovenia. The miners were well organised, and socialism was popular in the late 19th and early 20th centuries.

In the Rondel Tower of the east wing there's a mock-up of the 'call man', the unspeakable so-and-so who summoned miners to work every day at 03:30 by hitting a hollow log with a mallet in the town centre. At the bottom of the Mercury Tower at the start of the south wing is a Plexiglas cube filled with drops of mercury and 15 halogen lights on tracks, representing the number of levels in the mercury mine here.

One large room in the south wing is given over entirely to the bobbin lace (klekljana čipka) woven here in broad rings with distinctive patterns. Some 40 different motifs run the gamut from the usual hearts and flowers to horseshoes, crescents and lizards. Check the tablecloth that measures 3m by 1.80m. It was designed for Madame Tito and took 5000 hours to make.

An exhibition on the 2nd floor of the south wing traces Idrija history in the 20th century - from WWI and the Italian occupation to WWII and the birth of socialist Yugoslavia. Check out the huge, bright-red hammer and sickle in the last room; it once adorned the entrance to the mercury mine.