A line of 830 bunkers was to defend the capital city of Prague
The immediate protection of Prague was provided by a fortress half-arc line consisting of 830 light fortification buildings. Even today, after almost 75 years, we can find bunkers in the vicinity of the capital that have survived the liquidation works from the occupation.
Although the emphasis on the location and method of fortification of Czechoslovakia’s defences adapted to the current situation during the second half of the 1930s, one of the main anticipated enemy attack directions remained the same – from the west towards Prague and further inland. Therefore, the Directorate of Fortification Works, which directed the construction, began building the inland interceptors that crossed the republic from north to south. On these lines of light fortifications, which consisted overwhelmingly of vz. 37 bunkers, the enemy’s advance, which would break through the western positions of our army, was to be stopped, or at least slowed down.
The stubborn defence of Bohemia was a necessity not only from an economic but above all from a psychological point of view. This difficult task was further complicated by the fact that a considerable part of this territory was inhabited mainly by a hostile German minority. Therefore, unlike fortifications in other parts of the country, no defensive line was drawn in the area of western Bohemia in the immediate vicinity of the border. This made it impossible to count on a long-term defence of the front lines. The expected advance of the enemy from the west further into the interior of the country – mainly towards Prague – was to be halted by a system of interconnected inland lines. The subsequent retreat of troops further into Moravia and then Slovakia was to be covered by two more similar vertical lines of defence

Vertical partitions
General Karel Husárek’s fortification programme of November 1937 thus envisaged a total of three interception lines. The first was to lead from the north of Mimona – the so-called Liběchovská crossbar, followed by the so-called Pražská line. The line of the fortified bridgehead of Prague was to end at Slap nad Vltavou, from where the defensive zone continued along the Vltava River to the south. The second line was planned on the Bohemian-Moravian Highlands on the route Bouda – Ústí nad Orlicí – Litomyšl – Přibyslav – Horní Cerekev – Slavonice. The line of „last hope“ can be called a position on the Moravian-Slovak border, which was to lead from Opava through Hranice, Napajedla, Kuty. However, the construction of these two eastern fortress systems was postponed after the occupation of Austria in order to spend maximum resources on the accelerated strengthening of the defence of the southern border. Thus, only the first of these systems, consisting of three main lines, was implemented. One of them was the Prague Line.
The heavy objects remained only on paper
The immediate protection of the capital was provided by a half-arc line running at a distance of about 30 kilometres from the metropolis and starting in the south at the Vltava River and continuing through the Brdské ridges, the Berounka River, dense forests in Kladno and open terrain in Slánsko to Dusniki on the right bank of the Vltava. However, the northern part of the Prague bridgehead was fortified as early as the summer of 1936, at which time 77 fortifications of the model 36 were built.
After the vz. 36 was replaced by a more modern version of the objects – vz. 37, it was decided that this type would be built in locations where there were already previously built vz. 36 fortresses. The northern part of the Prague Line between the Vltava and the Berounka rivers was thus actually covered by two lines, which only partially overlapped in their course and firing fans. This line was to face the enemy advancing in the direction of Saxony and Bavaria. Before the enemy troops could stand in front of the capital, they had to cross three lines: near the border at the foot of the Ore Mountains, inland along the rivers Blšanka and Ohře, and the Prague Line, which in the terminology of the time was called the Outer Defence Line of Prague. The Prague Line, subsequently stretched as far as Mělník, numbered a total of 830 objects as of 15 October 1938, when work stopped. All this on a line 112 kilometres long.
In the plans of the strategists we could also find several so-called closures consisting of heavy fortifications. However, the construction planned for 1939-1940 never took place. The occupation authorities destroyed most of the bunkers of the Prague Line during the liquidation work in 1939-1943. The first blasts began near Slany on the afternoon of 14 June 1939. The Germans spared only a few bunkers that were too close to buildings, bridges or power line poles. Such objects were concreted practically to the ceiling. On the Prague Line, the occupiers did not blast away only 78 of the 830 structures, about half of which ceased to exist in subsequent series of blasts by 1943. Thus, only one vz.36 bunker and 37 vz.37 buildings remain today.
Forced oblivion
The Prague Line remained virtually forgotten for many decades after the end of the war. For ideological reasons, the communists did not want to commemorate the symbols associated with the First Republic. It was only in the 1980s that some enthusiasts tried to map the course of the line from archival materials. The reconstruction of the first bunker of the Prague Line did not begin until the spring of 1991, when the Krinke family from Kladno set about reconstructing the A-3/41/B2-80 building, located by the wall of the castle garden in Smečno. Tons of material had to be extracted from the almost completely concreted building.
Now the excavation is used as a museum. The Krinke family later reconstructed the only preserved building in this area, the vz.36, located above the secluded village of Mlýnek u Drnu. This bunker has been fitted with camouflage paint, guts, and interior furnishings including shooting tables or original gun covers, thanks to military history fans. The building was not shot down during the Protectorate simply because it is located immediately above the aforementioned solitude. However, the Nazis did not spare the bunker just 200 metres to the north – the IXb/44/C building was turned into a ruin after being shot.