Železna jama ('The Iron Cave') is located on the isotope karst of the westernmost area of ​​the Posavje hills near Gorjuša near Domžale. The cave visit is organized with a regular guide service and open for sightseeing. Like all other caves, this was also shaped by water. The rain fell on the humus surface as rain. Carbon saturated then penetrated through the hair or crack in the upper layer and eroded it, and deposited the rock in the form of hard water (not as a gravel cluster or rock). The age can not be determined precisely, but we know that water has been created by it for millions of years. The temperature in the cave varies according to the season. In the summer it is lower than in winter, because the rock on the ground heats up in the summer, and the heat is only emitted half a year later. Why is it called the Iron Cave? These local sources do not mention. Maybe the locals call it because they once dug iron ore from the cave. This also explains the remainder of the melting furnace with iron slag. Structure: the original entrance abyss opens on the eastern slope of the sink. The current, artificial entrance passage begins at its edge. The cave extends southwards under the sink, which is not a rare occurrence on our karst. The Iron Cave has three halls, which are interconnected by the ditch and bridges that are part of the tourist routes.

In 1962 and 1963, when the cave was arranged for a tourist tour, the western side, where the cave was closest to the surface, made an eight-meter-long artificial entrance. The original vertical fireplace remained unchanged. Even the eastern wall with the levels of the underground stream has preserved the original characteristics. Along the fracture there are several corrosion boilers and fireplaces. On the west wall, some cracked rocks had to be removed for safety reasons. The cracks are drawn parallel to the slopes of the sink. There are many grooves in the cave. Typical of the caves are also the fallow stones, which are being guided by the wind during its development. The height of the first and second main halls is greater than their length and width. The spaces are in the shape of a larger abyss. In particular, the first one downwards narrows and gets under the concrete path the shape of the gallery, which is barely a meter wide at the bottom. The original hall could be called the Buried Hall. It is also under the ceiling, above the meter high, a stalagmite. On the eastern wall there are some smaller sights of the notch and the shape which the cigar was called in Postojna Cave. Both halls bind the meter long strait with visible traces of water flow below the ceiling and in the ground. At the bottom of both halls, the water is running out, as there is a loamy threshold at the bottom. The second hall has a broader bottom, which is artificially raised and leveled. The ceiling is crisp and smooth.

In some places in the western wall, an aggressive slap lined up small holes and sloppy-like drains. Since the water of the water is flat through the vertical wall, t grows. i. Signs of growth: these are small, hedgehog-like creatures (Annex - Figure 10). There are several steep or vertical cracks and cracks in the walls of both halls, where, due to internal pressures, the cavities were separated and in some places rocky blocks were placed.

The design of the All Iron Cave is a double, galley-connected abyss, which was deepened together by lowering the erosion base in the wider area of ​​the karst karst and spreading in contact with the sediment. The current and former water flows that pass through the ceiling are directed towards these two pitches.
Although the Iron Cave is small, its tiny forms are variegated. From evacuation shapes, depressions, facets, corrosion boilers, remains of the epoxy cross-section of the trench and gallery are represented. Of the accumulation forms, there are rare stalagmites and stalactites, significations of protrusions, cotton buds, smaller curtains, special shape - cigars. Also, the cave is interesting due to cracks caused by weight relief or pressure on the walls of larger caves.