Jihlavské podzemí

Jihlava Cellars

Useful Information

photography — Map of Iglau (Jihlava) by Merian, Czech Republic. Public Domain.

Location:	Hluboká 1, 586 01 Jihlava. From Prague E50 exit 112 Jihlava, 38/E59 exit Jihlava-centrum. Two parking lots on the Masarykovo náměstí (Masaryk Square). Just to the right of the church of St Ignatius on Hluboká námestí. (49.396970, 15.591471)
Open:	Historic Underground: Alpha - Civil Defense Shelter: APR daily 10, 11, 12, 14, 15, 16. MAY daily 9, 10, 11, 12, 14, 15, 16. JUN to AUG daily 9, 10, 11, 12, 14, 15, 16, 17. SEP daily 10, 11, 12, 14, 15, 16, 17. OCT daily 10, 11, 12, 14, 15. Sewers: All year Sat 9, 11, 13, 15. Online booking required. [2023]
Fee:	Historic Underground: Adults CZK 80, Children (6-15) CZK 50, Children (0-5) free, Students (-26) CZK 50, Seniors (65+) CZK 50, Disabled CZK 50, Family (2+3) CZK 235. Groups (10+): Adults CZK 80, Children (6-15) CZK 40, Students (-26) CZK 40. Sewers: Adults CZK 150, Children (6-15) CZK 70, Students (-26) CZK 70, Seniors (65+) CZK 70, Disabled CZK 70. Alpha - Civil Defense Shelter: Adults CZK 80, Children (6-15) CZK 50, Students (-26) CZK 50, Seniors (65+) CZK 50, Disabled CZK 50, Family (2+3) CZK 235. Groups (10+): Adults CZK 80, Children (6-15) CZK 40, Students (-26) CZK 40. [2023]
Classification:	Cellar Sewage System World War II Bunker Secret Bunker Replica Underground Mine
Light:	Incandescent Electric Light System
Dimension:	L=25,000 m, VR=25 m.
Guided tours:	Historic Underground: L=440 m, D=45 min, Min=3, Max=45. Sewers: D=1 h, L=1 km, Min=5, Max=20, MinAge=6. Alpha - Civil Defense Shelter: D=45 min, Min=3, Max=10, MinAge=6.
Photography:	allowed
Accessibility:	no
Bibliography:
Address:	Jihlavské podzemí, Hluboká 109/1, 586 01 Jihlava 1, Tel: +420-565-597-579 (Cashier), Tel: +420-565-597-570, Tel: +420-603-518-110. E-mail: Turistické informazní centrum Jihlava, Jihlava, Masarykovonám.2, 58601, Tel: +420-567-167158.
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then. Please check rates and details directly with the companies in question if you need more recent info.

History

14th century	construction of the first level of cellars.
16th century	construction of second and third level of cellars.
17th century	brick lining and connecting corridors created.
1957	opened to the public.
1969	tunnels closed for the public due to the Cold War.
1978	svítící chodba (shining corridor) discovered.
1991	tunnels reopened to the public after the Cold War.

Description

Jihlavské podzemí (Jihlav Underground) is also called Jihlav Catacombs, but actually these are not catacombs. It's a collection of underground spaces which were used for various purposes, but never as catacombs. The term catacomb has become a sort of synonym for underground spaces, while it actually means underground cemetery. The underground spaces have a total length of 25 km, in an area of 5 ha which covers the whole city center. The structure is quite complicated with numerous levels, which is quite obviously a result of its origin as separate cellars. They were built as storage cellars by the merchants of the Medieval city, and at some point they reached a size where the different cellars connected. It seems there was a reason to connect the cellars, probably it made the transfer of goods easier. But why they did it is actually not handed down.

When the underground structures were rediscovered, nobody knew about their existence anymore, and so there is no background info at all. The first researchers thought they found abandoned silver mines, because there was silver mining in the area. But the structure did not fit, the passages did not follow ore veins. Then they thought it might be military structures, but again it was not possible to find out the strategic importance of the tunnels. Finally, they realized, that the structure of the spaces works quite well as storage for goods. Jihlava was located on an important crossroad of Medieval trade routes and when silver mining became unprofitable, trading and crafting became more important. It's obvious that there were a lot of unemployed miners available to dig the cellars. The reason why cellars were used for storage is also obvious. First it was very good for many vegetables and other food, and then the size of the storage was restricted by the walls of the Medieval city. It was not possible to build additional storage in the protection of the walls and building outside was too dangerous. But it was possible to use the underground.

The rocks of the underground are crystalline rocks like granite and gneiss. They are very hard and thus require experienced miners to dig the passages. On the other hand the rocks are very stable and the passages do not need much support. The miners worked in pairs, one dug and the other carried the rubble away. Digging by hand with hammer and chisel was a hard job, they managed only 2.5 cm of passage per day.

There are actually three phases of construction. During the 14th century the first level of cellars was dug at a depth of 2 m to 4 m. It seems in the 16th century they were not sufficient anymore, and so they were extended with a second floor at 4 m to 6 m, and a third floor at 8 m to 12 m. In the 17th century several sections were connected by short connecting corridors, and some corridors were supported with a brick lining. It seems the drainage of the village also used the cellars, in the way which was used by miners for centuries. Some passages became adits by the addition of a drainage channel in the middle, the water flowed simply by gravity and accumulated in sumps. The underground passages are ventilated by wells leading from the underground to the surface, which function as ventilation shafts. There are numerous small tunnels which are only 70 cm wide and between 1 m and 1.7 m high. They were too small for cellars, they were actually dug as a sewage system, and so the size was sufficient for the sewage and the occasional inspection tours. Some of them were later reinforced and connected to the new sewer system and are in use until today. But the end of the cellars began in 18th century, the unused cellars were either abandoned or transofrmed into sewers. During the 19th century the construction of water mains, gasification and the construction of new houses, destroyed many cellar, they were filled in. Or they flooded when the old drainage system was blocked.

During the German occupation in World War II a part of the corridors was modified as air raid shelters. With the end of the war they were abandoned, the people had other problems. But in 1957 about one kilometer of corridors was made available to the public for the first time. In the 1960s, most corridors were reinforced with concrete, they were cleaned and the medieval drainage system was restored. Only the tourist section was left in its original state. But in 1969 the tourist tunnels were closed, obviously a result of the Cold War. They were reopened after the Cold War, in 1991.

The highlight of the passages is the svítící chodba (shining corridor), which was discovered in 1978 by speleologists. The walls are covered with a milky coating which looks whitish in the light, and after it was exposed to light it glows green for some time. This is actually not hard to understand, it's called phosphorescence and was once used to paint the arms of clocks, so it was possible to read the time in darkness. The actual mystery was, why the walls were covered by phosphorous. Again there were numerous theories, for example that the phosphorous was released from the bones of monks who are buried above. Or that it was formed by unknown organisms. However, the most likely explanation is, that the walls were painted during World War II by the Germans, so there was some light when other light sources went out during air raids. The tunnel was used as an air raid shelter, but if it was intended for the public or only for Nazi officials is unknown. The corridor is located about 11 m below the surface, is 2.1 m wide and 2.9 m high.

There are three different tours. The Historické podzemí (Historic Underground) tour shows the Medieval storage cellars and the famous shining corridor. Since 2013 it also has exhibits explaining the medieval mining, like a mine replica, ore processing, minting, and Jihlava's mining law. Also, there is an exhibit on pottery from the 14th century and a mineral exhibition. The Kolektory (Sewers) tour is dedicated to the sewers and shows both the Medieval sewers and the modern sewers. The tour shows all three levels of the sewer system, especially the spinal branch at a depth of 20-25 m, but also the 16 m and 10 m levels. To reach the different levels it is necessary to climb iron ladders. There is also a small museum at the end of the tour which shows a documentation on the sewer renovation, a collection of mining lamps and pure silver minerals. The Kryt civilní obrany (Civil Defense Shelter) shows the Cold War civil defence bunkers. It starts with an exhibition on the 20-AUG-1968 when Warsaw Pact troops had crossed the national borders of Czechoslovakia. As a result the tourist tunnels were closed and a system of civil defence tunnels was built in the cellars. It included air filters, radiation meters, hygiene supplies, and sanitary facilities. The city had 83 shelters during the seventies and eighties. The tour is also called Alfa (Alpha) after the code name of the visited bunker.

All tours start at the ticket office. The ticket office is open 30 minutes before the first tour and closed when the last tour leaves for the tunnel. Be there at least 15 minutes before the tour starts, even if you have booked online. The time is needed for organisation, the handing out of the helmets, meeting the guide, and a security briefing. The tours either have electric light or headlamps are provided with the helmets. The entrance to the cellars is in the same building, the bunker tours walk together with the guide to the entrance at Masaryková náměstí 6.