Bratislava Fortifications Bratislava fortifications usually refers to the medieval city fortifications of Bratislava , the capital of Slovakia , of which one gate and two sections of walls remain today . The Bratislava Castle was also heavily fortified . Other fortification systems were built in the following centuries , including a World War I artillery fortification system and World War I shelters , system of bunker s and fortifications built by the First Czechoslovak Republic between the World Wars , World War II aircraft raid shelters , fortifications built by the Nazi Germany in the city during World War II and finally Cold War - era city defenses including a system of 8 , 602 air raid and nuclear shelters capable of holding over 760 , 000 citizens , far more than the number of inhabitants . The pinnacle of the communist era city defense was a military rocket base located on the Devínska Kobyla hill , the highest point in the city . Medieval fortification system . The medieval city fortifications are the system of fortifications of the city of Bratislava , the capital of Slovakia , of which one gate and two sections of walls remain today . Most of the medieval fortification system was demolished in the year 1775 by the order of Empress Maria Theresa of Austria , the rest being torn down in the 18th and 19th centuries . The only remaining consistent stretch of Bratislava city walls running from the St . Martin ' s Cathedral towards the intersection of Na vŕšku Street and Kapitulská Street is inaccessible to the public , despite not only being a tourist attraction but also a valid shortcut in the city center . History . Construction of the medieval fortifications in Bratislava ( known as Pressburg / Poszony for most of its history ) started in the 13th century . By the end of the 14th century , there were three gates leading to the town : the Michael ' s Gate ( north ) , Vydrica Gate ( west ) and Laurinc Gate ( east ) . In the 15th century another smaller gate was added : the Fishermen ' s Gate ( south , leading to the Danube ) . The suburbs gradually grew around the fortification walls , which were fortified in the 15th century with embankments and dykes on the order of King Sigismund , after a Hussite invasion . The town ' s outer line had five gates : the Kozia Gate , and gates at Suché mýto , Špitálska , Dunajská and Schöndorf ( today ' s Obchodná ) streets . The city fortifications were made of stone , walls being 130 - 160 centimeters thick . According to Slovak historians , the foritification system was built as a whole from the end of 13th century until the half of 14th century . The top of the walls was crowned by battlement . Due to the Turkish threat in the 16th century , the fortifications were reconstructed by Italian builders specialising in fortress building . Other changes were also planned in the 17th century , but only castle fortresses were implemented . However , as the town ' s inner walls were slowing the town ' s growth , Maria Theresa of Austria allowed the demolition of the fortifications in 1775 . Demolition continued until 1778 , the moats were filled and the town united with its suburbs . At the beginning of the 19th century , the outer walls were also demolished . The remaining stretch of city walls was reconstructed in two phases between 1975 and 1991 . The walls starting at intersection of Kapitulská Street - Na vŕšku Street and ending at Eszterházy Palace comprised the first phase and the remaining stretch ending at St . Martin ' s Cathedral comprised phase two . Bastions . The system of fortifications of medieval Bratislava contained several bastions and guard tower s . The large horshoe - shaped bastions protruding into the area between the inner and outer wall rings usually had their own name . The smaller , half circle - shaped ones were usually referred to in their relation to other prominent bastions or city gates in their vicinity . Bastions were built more extensively comparatively late , only after cannon s improved , and especially after the Battle of Mohács in 1526 . However the bastions named Enemy of the Hungarians ( Nepriateľ Uhrov ) , Lugisland , Bird ' s bastion ( Vtáčia bašta ) , Bastion at the upper bath ( Bašta pri hornom kúpeli ) , Gunpowder bastion ( Prašná bašta ) , Bastion behind the cloister ( Bašta Za kláštorom ) , Butchers ' bastion ( Mäsiarska bašta ) , Bakers ' bastion ( Pekárska bašta ) and Shoemakers ' bastion ( Obuvnícka bašta ) were all built before the year 1520 . This is a list of named bastions running clockwise from Michael ' s Gate towards Laurinc Gate then Fishermen ' s Gate then Vydrica Gate and then back to Michael ' s Gate . The south part of city walls were protected enough by the environment of the river Danube creating an uninhabited system of small tree - less islands . The only two remaining bastions today are Gunpowder bastion ( Prašná bašta ) which was redesigned as a residential house at Zámočnícka Street No . 11 and the remains of Shoemakers ' bastion ( Obuvnícka bašta ) were included into the house at Hviezdoslavovo námestie No . 11 , today it contains the coffeehouse " Korzo " ( not visible from the outside of the building ) . Today . Today , only Michael ' s Gate , a short stretch of former wall by it and a section by St . Martin ' s Cathedral approximately 200 metres in length have survived . The section by St . Martin ' s Cathedral was renovated after a massive demolition in the area under the castle due to the construction of an access road to the Nový Most bridge , and parts of fortifications were uncovered . The narrowest house in Europe is located on Michalská Street , near the Michael ' s Gate . The city Bratislava owns this stretch of city walls from the year 1993 . In the year 2000 , the city rented the structure to an NGO " Tovarišstvo starých bojových umení a remesiel " . In the year 2001 the city walls were declared inaccessible to the public and big metal fences were installed at the entry points . According to a statics expert , the structure remains intact and there is no danger of large pieces falling apart . On the other hand , small pieces of outer layers of the structure are peeling off and pose a hazard to pedestrians and cars passing down Staromestská street . Parts of the fortifications are covered by scaffolding to strengthen it . For some reason , the scaffolding is owned by private companies which used it immediately to install oversized advertisements . In 2010 , strong wind damaged the wooden observation deck near St . Martin ' s Cathedral so badly , that it had to be deconstructed . The Bratislava city company " Mestský investor pamiatkovej obnovy - spoločnosť Paming " is planning the reconstruction of the longest fortification stretch at least since 2008 , but as of 2011 no progress has been made . The city of Bratislava claims it does not even have the budget to apply for a grant from the Ministry of Culture , because it requires mandatory co - financing . According to Jozef Hrabina , head of the Paming company , the estimated cost of reconstruction , including research and project documentation is 1 . 7 million euro . This stretch of fortifications contains the only remaining tower - the Bax tower ( " Baxova veža " ) , although other sources claim it is the Bird tower ( " Vtáčia veža " ) . The unique city walls continue to be inaccessible to the public , used extensively as sleeping place for the homeless . Bratislava Castle fortifications . Most of the extensive fortification system of the Bratislava Castle survived until present , including numerous gates . World War I artillery fortification system . In the spring of 1914 , Austria - Hungary was facing military defeat for the first time during the war as Russia n troops advanced towards the Carpathian mountains . The situation caused deep concern within the Austro - Hungarian military as the failure to defend the Carpathians would allow the enemy to access central Hungary , including Budapest . One of the measures taken to prevent this was the decision to fortify the city of Poszony ( today Bratislava ) . Goal of the fortification system was to prevent the Russians from crossing the Danube river and thus prevent the encirclement of Vienna ( something the Prussians attempted in 1866 in the Battle of Lamacs during the Austro - Prussian War ) and denying access south towards the Hungarian mainland . The fortification complex consists of individual artillery posts grouped together into strategic points . The artillery posts consisted of artillery caverns ( ) used to shelter soldiers and ammunition from enemy counter - fire and close to them were the actual artillery batteries . The goal of this artillery was long - distance circular artillery defense of the city . They were located on hills with good outlooks below , today corresponding to the areas of Dúbravská Hlavica , Dlhé Diely , Sitina , Lamač , Klepáč , Americké námestie , Kamzík and Rösslerov lom . All of them are located within the Devín Carpathians mountains and the Bratislava Forest Park . Fighting in the Carpathians ended in May 1915 due to a German break at Gorlica . Russian troops were pushed back and they did not return again during this conflict . Due to this development , the fortification system was unused in combat and left partially unfinished . Description . There are altogether 32 or 42 ( depending on the source ) surviving artillery caverns . Some of them are partially collapsed or their ceiling is in danger of collapsing . Next to some of the caverns , there are still distinguishable platforms for the artillery ( which did not survive ) . The main construction material was concrete . Today . Today , the fortification system is largely unknown to the public , although the artillery caverns themselves are accessible and visited by experienced hikers . Some of them serve as sleeping places for the homeless . There are currently no plans to restore the cultural monument or to use it to attract tourists . First Czechoslovak Republic fortification system . Despite being in direct violation of international treaties that Czechoslovakia was bound with at the time , it started a large - scale construction of border defenses and fortifications . First military fortifications were constructed in Petržalka in 1934 , by order of general Šnejdárek , being among the first fortification objects built on the area of Czechoslovakia after World War I . Second wave of construction commenced in 1937 which turned the defenses into a consistent fortification line . Overall , the Bratislava section of the Czechoslovak fortification line was considered to be an example to other sections and Bratislava fortifications were complete and ready for action by autumn 1938 , including all auxiliary objects , command posts , terrain obstacles , inner fittings of all objects . The fortification system was equipped with weapons and ammunition and manned by the 1 , 500 strong Border Battalion 50 ( ) . The construction of the Petržalka fortifications was carried out by the construction company Ing . Rudolf Frič from Bratislava . The following is a list of heavy fortification bunkers built by the First Czechoslovak Republic :