On the slopes of Blatenský vrch (Blatná Hill) we can find the VLČÍ JÁMY (WOLF HOLLOWS), also translated as Wolf Pits) – a protected nature monument.
Vlčí jámy is one of the souvenirs of the extraction of tin ores from the Wolfgang mine. The pits were created gradually. In the 16th century a large chamber with the height of 25 metres was excavated from out of here; the roof of which later caved in opening up a sink-hole on the surface. In the course of time rock fell from the sides and Vlčí jáma widened even more. Old mining works from the 16th century reached 35 metres under surface at the deepest. In the 18th century the local lode was mined down to the depth of up to 60 m under surface and it was step-mined down to the depth of 80 m under the surface, which was almost unheard of at that time. Today we can see this interesting natural and technical monument from a observation point at the beginning of the sink-hole. From the upper side edges it is possible to see the remains of old drifts and chimneys, through which the miners could sometimes hardly squeeze themselves.
Several dozens of meters up the hill there is another remnant from the tin mining – the Jiří Mine. This mine that also dates back to the 16th century is now a sink hole stretching to the distance of approximately 150 m. It has collapsed all the way to the surface in a length of about 80 m. In some places it is up to 20 m deep and very narrow. Today it is partially filled with rocks released from the steep walls. According to historical records the mine reached the depth of up to 50 m.
This protected nature monument is currently known under the name of Ledová jáma (Ice Pit). Considering the significant depth of the collapsed sink-hole a special microclimatic regime with only a very imperceptible air circulation was created here. In the summer light warm air stays on the surface and does not descend into the sink-hole. On the contrary, during the winter the hole is cooled down by heavy cold air and thus ice is formed here, which stays at the bottom of the pit even throughout the summer. The relatively high elevation above sea level of the locality also helps keep the year-round temperature at a level below freezing. In old documents an interesting report exists that six wagon-loads of ice were extracted to treat injured soldiers from the Battle of Leipzig in 1813. Nowadays one can climb down steps into a narrow sink-hole up to a point, from where it is possible to see an ice layer even in summer months .