Kaunas Fortress Kaunas Fortress ( , ) is the remains of a fortress complex in Kaunas , Lithuania . It was constructed and renovated between 1882 and 1915 to protect the Russian Empire ' s western borders , and was designated a " first - class " fortress in 1887 . During World War I , the complex was the largest defensive structure in the entire state , occupying . The fortress was battle - tested in 1915 when Germany attacked the Russian Empire , and withstood eleven days of assault before capture . After World War I , the fortress ' military importance declined as advances in weaponry rendered it increasingly obsolete . It was used by various civil institutions and as a garrison . During World War II , parts of the fortress complex were used by the governments of Nazi Germany and the Soviet Union for detention , interrogation , and execution . About 50 , 000 people were executed there , including more than 30 , 000 victims of the Holocaust . Some sections have since been restored ; the Ninth Fort houses a museum and memorial devoted to the victims of wartime mass executions . The complex is the most complete remaining example of a Russian Empire fortress . Background . The city of Kaunas is located at the confluence of two rivers , the Neman and Neris , which link Lithuania ' s interior and its capital , Vilnius , to the Baltic Sea . The Baltic peoples had created significant domains by the 1st century , and came into conflict with the Scandinavians and the Slavs ; the Teutonic Order began targeting Lithuanian lands at the beginning of the 13th century . Since Lithuania was heavily wooded and its lands were often impassable , its interior was most approachable along its rivers when frozen and during the short dry harvest season in late summer . In response to this vulnerability , defensive structures , including a brick castle in Kaunas , were in place at various points on the Nemunas River by the 14th century . The city was first mentioned in written sources in 1361 ; it received Magdeburg rights , regulating its autonomy and establishing trade protocols , from Vytautas the Great in 1408 . An outpost of the Hanseatic League was created there in 1441 . By the end of the 16th century Kaunas had become a major regional trade center , but plagues , fires , and wars adversely affected the country and city during the 17th and 18th centuries . Following the partitions of the Polish – Lithuanian Commonwealth at the end of the 18th century , Lithuania was incorporated into the Russian Empire . Two major 19th - century projects contributed to the city ' s revival . The Augustów Canal , completed in 1832 , linked the Neman to the Black Sea , and a rail line linking Saint Petersburg , Warsaw , and Germany via Kaunas was completed in 1862 ; it was part of a limited network of western Russian railways . Russia ' s western borders needed support , and fortresses existed or were being built in Latvia , Ukraine , and Belarus . The concept of building a fortress in Lithuania was discussed without result in 1796 , but became a critical concern after the French invasion of Russia in 1812 led by Napoleon . The Grande Armée managed to cross the Nemunas near Kaunas on its drive towards Moscow without major difficulties . An increasingly unified Germany troubled the Empire during the second half of the century . A fortress in Kaunas would present an obstacle to attacks from the west , preventing further incursions towards Riga and Vilnius . In order to control the region , attackers would need to first neutralize Kaunas . Facing this possibility and evaluating the natural advantages of the city , Russian officials decided to construct a fortress there . After several delays , on July 7 , 1879 Tsar Alexander II issued an edict ordering its construction . Construction . The first design was overseen by Generals Nikolay Obruchev , Konstantin Zverev , and Ivan Volberg . As originally planned , the fortress encompassed a huge site , consisting of seven forts and nine defensive batteries arranged in concentric loops . The plan included support buildings and infrastructures , such as barracks , new roads , and an ammunition depot . Construction began in 1882 ; about 4 , 000 workers were mustered for the project . The principal structures were concentrated in Freda , Panemunė , Aleksotas , and the new section of the city . The project significantly affected the daily life of Kaunas residents , and there were plans to detach the fortress into an independent administrative unit governed by a military board ; its commandant wrote that " There is no city of Kaunas , there is only the Fortress of Kaunas . " The first forts were built using bricks reinforced with thick ramparts of earth , which were incorporated into the surrounding relief , making them harder to breach . They were symmetrical , usually having five faces , with positions for infantry and artillery . These forts were built according to the standard Russian brick fort design of the time . Therefore , the first seven forts were very similar ; they differed only in the layout of their interiors , their integration into the surrounding relief , and in some construction details . They would also be renovated in slightly different ways . Batteries were built between adjacent forts ; these were fortifications containing various types of artillery , located along the fortress ' outer lines and usually erected on the hills . The first construction phase was completed in 1887 . The fortress was designated first - class in that year , marking its importance and defensive capabilities , and Otto Klem was named its first commandant . At the same time , administrative rules were established to manage the fortress ' impact on the city and its surrounding areas ; the height of the fortress ' civil buildings was restricted . During 1890 work began on an eighth fort , known as Linkuva ; new construction techniques were introduced , particularly reinforced concrete . The Linkuva fort became the most modern entrenchment , equipped with electricity , sewerage , and casemate s for a garrison of 1 , 000 personnel . At the same time , massive groundworks were laid along with additional defensive structures , effecting the complete enclosure of the city center between the Rivers Nemunas and Neris . By 1890 , seven forts had been completed , supporting roads had been constructed , and a railroad bridge over the Nemunas had been adapted for military transport . By now , expenditures on the fortress had amounted to over nine million rubles . The first bricks for a church that would serve the garrison were laid in 1891 ; it was completed in 1893 . The following year construction began on a dedicated narrow gauge railway . The Ninth Fort , begun in 1903 , was the first of its kind in the Empire . The structure was a trapezoid , encompassing one infantry rampart , and was equipped with two armored watchtowers , electricity , and ventilation . The walls of its cannon casemates were covered with cork to reduce firing noise . The cost of this single fort was 850 , 000 rubles . The complex of forts and defensive structures was divided into four sectors . The first followed the left bank of the Nemunas to its confluence with the Jiesia River and included the three earliest forts . The second sector extended from the Jiesia to Pažaislis monastery and included two forts . The third extended from the right to the left bank of the Nemunas ; this sector also contained two forts . The fourth and last sector stretched from the right bank of the Neris to the left bank of the Nemunas , comprising two forts , including the newest – the Ninth Fort . As new building and weapons technologies developed , the fortress was repeatedly renovated in order to maintain its military effectiveness . In 1912 an expansion and reconstruction initiative was launched . This project called for twelve new forts along with batteries , support buildings , and defensive structures . Its completion was scheduled for 1917 . The older forts were to be completely encircled by the new construction , which was meant to employ the newest military technologies . During the early realization of the plan , new defensive entrenchments were built and the old forts were strengthened with concrete . However , when action began on the Eastern Front during World War I , work on the fortress was halted . In 1915 only one fort , the Ninth , conformed with the new technological criteria , while the Tenth Fort was only partially built . The complex then covered about and contained a internal railway , power plant , water supply system , mill , bakery , brewery , food bank , and telegraph . Despite the fact that the fortress ' renovations and new construction had not been finished , it presented a formidable challenge to its attackers . World War I . In 1915 , Germany and the Central Powers began an offensive against Russia and advanced towards Lithuania and Kaunas . The German army reached Kaunas Fortress in July 1915 . At that time , about 90 , 000 soldiers , commanded by Vladimir Grigoriev ( ) , manned the fortress . To attack the fortress , the Germans brought four divisions to the operation , which were placed under the command of Karl Litzmann . To support this attack , the Germans constructed a railroad to transport their Gamma - Gerät howitzer . The howitzer ' s shell weighed about 1 ton with a range of . Several days into the siege more guns of various calibers were deployed . The German army concentrated its attack on the First , Second and Third Forts , which were the complex ' s oldest structures . The army did not surround the entire fortress , and its defense was able to regroup and resupply . On August 8 , the Germans intensified their bombardment , but the fortress garrison withstood several attempts to breach the defensive perimeter . Several days afterward , the bombardment of the fortress reached its peak ; its defenders sustained heavy casualty rates of 50 % to 75 % . On August 14 , over 1 , 000 defending troops were killed , but the Germans were unable to completely overcome the fortress ' defenses . However , on the next day , Gamma - Gerät shells destroyed the First Fort and the Germans transferred their attentions to the Second Fort . The fight was now within the confines of the greater fortress complex . At the cost of many casualties , the Third Fort ' s defenders delayed the advance of the Germans , but were forced to evacuate and retreat later the same day . The next day the Fourth Fort was abandoned and the Fifth Fort was conquered soon afterwards . In a chain reaction , the other forts began capitulating . Commander Grigoriev abandoned his post and escaped to Žiežmariai . When the Germans crossed the Nemunas river they captured the Sixth and Seventh Forts . The remaining two forts were captured soon afterwards . After eleven days of fighting , the fortress had been taken . The defensive forces sustained 20 , 000 casualties , and about 1 , 300 weapons were captured by the Germans . Grigoriev was arrested by Russian authorities , tried , and sentenced to fifteen years in prison for failure to properly perform his duties . He also suffered the revocation of all his awards , military degrees , and honors . The Germans used materials from the fortress elsewhere during their war against Russia . Researchers have identified factors contributing to the relatively rapid fall of the fortress . It had not been completely renovated ; its defenders were inexperienced ; the crew had been frequently rotated , and had not been able to familiarize themselves with the surrounding area and with the fortress . Although most of their experience lay in the defense of the fortress ' interior , they were dispatched to fight on open ground . When the combat moved outside the fortress , communication lines were disrupted by the German bombardment , and the fortress defense was unable to restore complete communication with the command center or with other forts . The absence of external support was a crucial factor in its fall . Interwar . Lithuania regained its independence on February 16 , 1918 and the old fortress was placed under engineering staff supervision . Those materials that had not been taken by the Germans were used to resupply Lithuanian military needs , and for the construction of the armored train " Gediminas " , named after the 14th century Grand Duke of Lithuania Gediminas . In 1920 , the Kaunas Fortress Board was formed and charged with the task of administering the fortress . Due to the development of new military technologies , its reconstruction was seen as a vast and inappropriate expense . The fortress ' armament was dismantled and the trenches were filled with scrap iron . Sections of the fortress were given to various civil institutions , while the army occupied the barracks of the former 28th Division . The Sixth and Ninth forts were used as prisons and the Central Archive was located in the Seventh Fort ; the Republic ' s official radio station was based in the fortress ; a gas chamber was installed in the gunpowder depot of the First Fort and used to execute condemned prisoners . Some sections were used as housing for the poor . As the city of Kaunas expanded near the complex , its roads became public streets . The structures and layouts of the new sections were influenced by the presence of the fortress . World War II . Adjustments to the secret protocols of the 1939 Molotov - Ribbentrop Pact assigned Lithuania to the Soviet sphere of influence , and it was occupied by the USSR in June 1940 . The fortress was then used to conduct interrogations and house political prisoners . The pact was broken when Germany invaded Russia on June 22 , 1941 . Nazi forces entered Kaunas on June 24 . The Sixth Fort became a POW camp for Red Army soldiers . Kaunas ' s Jewish population numbered between 35 , 000 and 40 , 000 ; few would survive the Holocaust in Lithuania . The Nazis , aided by Lithuanian auxiliaries , began massacring the Jewish population . On July 6 , acting under orders of the SS , Lithuanian auxiliary police units shot nearly 3 , 000 Jews at the Seventh Fort . On August 18 , in what came to be known as the " intellectuals action " , over 1 , 800 Jews were shot at the Fourth Fort . On October 28 , the " Great Action " took place — the residents of the Kaunas Ghetto were summoned , and over 9 , 000 men , women and children were taken to the Ninth Fort and executed . During the later course of the occupation , over 5 , 000 Jewish deportees from Central Europe would be executed at this fort . About 60 escaped in December 1943 ; they had been assigned to excavate and burn the bodies of earlier victims , as part of Aktion 1005 . Thirteen of these escapees were able to document the Aktion ' s attempt to hide the evidence of the mass murders . When Germany began losing the war and the battlefront approached Lithuania , the German defense began attempts to prepare a defensive in Kaunas , including the use of the fortress . The Nemunas River was labelled " the line of catastrophe " , and Adolf Hitler called for its defense at any price . On August 1 , 1944 Kaunas was captured by the Red Army . The remaining fortress structures were used for military needs and several of the original structures were demolished or redeveloped . The number of deaths at the fortress during World War II vary by source ; the United States Holocaust Museum gives detailed descriptions of the deaths of about 18 , 500 Holocaust victims . Other sources mention 30 , 000 Jewish deaths , with total number 50 , 000 . Post - war . Lithuania remained a Soviet Socialist Republic until 1990 . In 1948 , the headquarters of the 7th Guards Cherkassy Airborne Division was established in the fortress ' commandant ' s headquarters . The barracks were used by the 108th paratroopers regiment and the Fifth Fort served the air defense regiment . Most of the forts , however , served as depots or housed farming organizations . During the postwar expansion and development of the city , parts of the fortress were dismantled ; as part of the construction of Kaunas Polytechnic Institute the ground - level entrenchments of one defensive sector were destroyed . In 1958 , the Ninth Fort was dedicated as a museum . During 1959 , its first exhibition was opened , memorializing the crimes that had taken place there . The museum later expanded its scope to cover the fortress ' entire history . A tall memorial to the victims was constructed there in 1984 . However , the Soviet military occupied most of the fortress until Lithuania re - established its independence . After the withdrawal of Soviet forces , completed in 1993 , Lithuanian military bases were established at several forts . As of early 2007 , only the Ninth Fort had been partly renovated . It is now devoted to the Holocaust and Lithuania ' s occupations by the Nazis and the Soviets . The museum , which holds over 65 , 000 artefacts , is sponsored by the Lithuanian Ministry of Culture . Since the early 2000s , it has received about 100 , 000 visitors per year and hosted Holocaust education seminars and workshops . In 2005 , the international project " Baltic Culture and Tourism Route Fortresses " was launched , with support from the European Union . Its goal is the promotion of transnational scientific cooperation in monument protection , along with the creation of strategies to reconstruct and manage fortresses in the region . Kaunas Fortress is a part of this project . In 2007 , Seventh fort was sold , new owners started the restoration process , since 2009 Seventh fort is open as a fortification and military museum and is the only brick fort in Kaunas suitable for safe visiting . In the 2000s , a variety of entities owned parts of the complex : the Ministry of Culture , the Ministry of Defence , the State Property Fund , and the City of Kaunas . The site still contains unexploded ordnance , although a 1995 project removed about 1 . 9 tonnes of explosives . Other restoration issues include uncovered wells , poor drainage and ventilation , erosion , possible chemical contaminants , vegetative overgrowth , and the presence of a protected bat colony . Despite the damage that it has sustained , the Kaunas Fortress complex is the most complete of the surviving Russian Empire fortresses .