The "Bunker" Museum of Lyash is one of the most scandalous and mythical sites of recent decades in Kaliningrad. Kaliningrad historian Sergey Trifonov has repeatedly claimed that there are hidden underground floors beneath this bunker, and possibly the Amber Room is located there. Whether this is true or not will be revealed in time, but for now, these are merely sensational statements.

The last commandant of Königsberg, Otto von Lyash, was in his bunker on Paradeplatz during the city's assault. Today, this is the "Bunker" museum. At the end of January 1945, General Otto Lyash ordered the construction of a new powerful bunker for his headquarters in the area of the hastily equipped new command post on Paradeplatz, based on a standard design previously developed by the planners of the Todt construction organization.

The bunker was built by the forces and resources of several organizations that continued to operate in Königsberg even after the total mobilization of their workers and employees into the Volkssturm and the construction of the so-called Eastern Wall. Among them were the branch of the Weiss and Freitag joint-stock company "Concrete and Reinforced Concrete Aboveground and Underground Structures," the central office of Julius Berger "Underground Construction," and others.

The protective and hermetically sealed doors were manufactured by Franz Schredter's company "Iron and Steel – Construction," as evidenced by the company stamps preserved to this day.

The limited construction time and shortage of qualified labor and specialists forced builders to assemble construction components (ventilation equipment, drainage devices, heating devices, pumping stations, air overflow valves, and others) — as the saying goes, "a little bit from everyone," fortunately, all of this was abundant in the ruins of the central quarters. The installation of this equipment was carried out by specialists from the limited liability company Scheffer and Walker.

By March 7, 1945, the bunker of the command group of the Königsberg fortress command post was ready. General Lyash justified his decision to move the command post from the basement of the main postal directorate as follows: "It was simply impossible for my headquarters to work calmly there. Any artillery shell, even of small caliber, would easily pierce the above-basement ceiling, which was almost at ground level."

The bunker is a perfect parallelepiped made of monolithic reinforced concrete and consists of two compartments along its length, separated by a continuous temperature-settlement joint. The total length of the structure is 42 meters, the width about 15 meters, and the height around 5 meters.

The bunker’s covering consists of a one-and-a-half-meter layer of reinforced concrete (with granite rubble and broken glass as filler), bituminous waterproofing, and a one-meter protective soil layer. The bunker has a corridor layout and includes 17 staff rooms and 6 auxiliary rooms (vestibules, sanitary units, technical and ventilation rooms). The thickness of the outer walls is 70-80 centimeters, and the inner walls 40-50 centimeters. The bunker is equipped with two dead-end type entrances with protective and hermetically sealed doors. Their closure is carried out using wedge bolts.

The engineering networks included: sewage, water supply, heating, supply ventilation, and drainage. The air pressure in the staff rooms was regulated by special overflow valves. There was also a water collection well that gathered groundwater, which was pumped into the city’s storm sewer system. The removal of sewage water was carried out similarly.

A phosphorescent (glowing in the dark) strip ran along the corridor walls. At each bunker entrance, there were round metal structures with conical roofs (former city transformer booths) for housing guards and personnel controlling access.

As noted earlier, the command group bunker was part of the command post of the Königsberg fortress commandant, along with the support group and the communications node.

All three components of the command post had telephone and radio communication and were connected by communication passages in the form of full-profile trenches (1.5 meters deep) with steep wooden walls covered by camouflage nets. The perimeter of the command post was patrolled around the clock. It was protected from the air by anti-aircraft battery fire.

On the eve of the Königsberg garrison’s surrender, envoys went to the last commandant’s headquarters at the request of Colonel Hefker, accompanied by a translator. Lieutenant Colonel Yanovsky, Captains Fedorko and Shpitalnik moved toward the bunker to deliver the ultimatum.

As Yanovsky recalled, the area was heavily clogged with destroyed equipment and corpses, everything around was burning. Barricades were everywhere, and a path that could be crossed in about half an hour took two hours to traverse.

Artillery fire on the scouted targets did its job. Otto Lyash noted that many went mad from such fire strikes. No one could withstand it. Some sources claim that the German position was initially hopeless, resistance was pointless, and stubbornly prolonging the finale increased losses (on both sides) and led to destruction.

The commander of the 11th Guards Army, Galitsky, recalled that the fascists had prepared all buildings for defense, with embrasures skillfully masked in the walls. Houses were connected by underground passages through basements. The enemy instantly sent fresh forces to the attacked section through them.

As Yanovsky recalled, Lyash did not want to sign the surrender order and take responsibility until the last moment. Lyash’s staff officers gave verbal orders to unit commanders to surrender, contrary to the commandant’s orders, during the envoys’ presence.

According to Galitsky, the city was ordered to be held at any cost. This was evident from Lyash’s actions. He feared either the encirclement of the garrison or the breakthrough of our troops to the city center, where his headquarters was located. Trying to prevent both, he was forced to disperse his forces, and thus to take advantage of this. Marshal Vasilevsky ordered not to cease hostilities, to keep the enemy under pressure, and not to allow the organization of a new defense.

Otto von Lyash was sentenced to 25 years imprisonment for war crimes on the territory of the Soviet Union. However, he was released already in 1955. Afterwards, he wrote books — "The Whip and the Carrot" and "Thus Fell Königsberg." In any case, in his works, Lyash tells his version of the war, the fall of Königsberg, and the regime, having his personal attitude toward everything that happened. The first interrogation protocol, held in the Central Archive of the Ministry of Defense (TsAMO), shows that Lyash unconditionally and freely provided all information. He answered questions fully and clearly. But after his imprisonment, returning to Germany, he became bolder and began writing his version of Königsberg’s fall.

Sources:

https://gid39.su/muzej-bunker-otto-lyasha/
Blog of Nikita Zagorny

https://www.forum-kenig.ru/viewtopic.php?f=40&t=114