Attempts on Hitler were preparing a sufficiently large number (it is believed that there were about 20). Some of them were carried out, some remained at the stage of designs. Many conspirators were uncovered and executed. In any case, the most famous assassination attempt on Hitler was the attempted July 20 1944 of the year, known today as the July 20 Conspiracy or the Generals Conspiracy. Then, in the course of the unsuccessful attempt, Hitler survived, and the result of the conspiracy was the execution of the majority of its participants and repression against their family members. However, the German military planned the assassination attempts on Hitler even before 1944. One of such attempts was undertaken by Major General Henning von Treskov, who did not share the Nazi ideology and established contacts with secret opposition groups that were going to remove Hitler from power, back in 1938 year.
Henning von Treskov - full name Henning Herman Robert Carl von Treskov was born on January 10 1901 of the year and came from a noble family of a Prussian officer. During World War I in 1917, at the age of 16, he volunteered to join the army, taking part in battles on the Western Front. In June, 1918 was promoted to lieutenant, and in July of the same year he was awarded the Iron Cross. Later he left military service for a short time, but he returned to the army as early as 1926. He took part in the Polish and French Wehrmacht campaigns. From 1941, he served as the first officer of the General Staff at the headquarters of Army Group Center on the Eastern Front.
Being in the service, he never particularly concealed his anti-Nazi and anti-Hitler views. It is known that he was extremely negative about repressions against Jews and political workers of the Red Army, trying to protest such orders. He told his colleague Colonel Baron Rudolf-Christoph von Gerdorf, if the orders to execute commissioners and “suspicious” civilians are not canceled, then “Germany will finally lose its honor, and this will be felt for hundreds of years. The blame for this will be laid not on Hitler alone, but on you and me, your wife and mine, your children and mine. ” History has shown that Treskov was right. Germany and the Germans still bear this cross, recognizing the crimes of Nazism, Hitler and his minions to humanity.
Treskov and his associates expected to remove Hitler, imagining his death aviation disaster. The planned assassination was preceded by long months of secret discussions, negotiations and preparations. The decisiveness of the conspirators grew with the defeats of the German army on the Eastern Front and received an impetus after Hitler, contrary to the advice of the generals, wanted to conquer Stalingrad and the Caucasus at the same time. The defeat of German troops near Stalingrad and the destruction of the whole German army played a decisive role. Hitler was supposed to disappear. And when in March 1943 the Wehrmacht officers managed to lure him to Smolensk, it seemed that the fate of the dictator was decided, but in reality everything turned out differently.
In January and February 1943, German generals Friedrich Olbricht, head of the Army General Directorate, and Hening von Treskow, the headquarters of the Army Group Center in Russia, developed a plan for the Fuhrer's assassination, the plan was codenamed Outbreak. The essence of the plan was to in March 1943 of the year to lure Hitler to the headquarters of the army group in Smolensk, where he did away with him. This event was to be the starting point for a coup in Berlin. An attempt could be made on the ground, but the conspirators planned to plant a bomb on Hitler's plane, sending it with him in the form of a parcel. In this case, the bomb was supposed to work already in the air during the return of the Fuhrer from Smolensk to Berlin.

Henning von Treskov
In early March, 1943, the conspirators gathered for the last meeting in Smolensk at the headquarters of Army Group Center. Although Admiral Canaris, the chief of the Abwehr, did not take part in this operation, he was aware of the planned events and contributed to the organization of the meeting, taking with him to Smolensk the officers of the headquarters of Hans von Donanie and General Erwin Lahousen. The last former officer of the Austrian army was the only one of the Abwehr conspirators who managed to survive the war, he brought with him several bombs to Smolensk. Fabian Schlabrendorf, a junior officer at Treskov’s headquarters, who was his adjutant, and the Major General himself, after conducting numerous tests, concluded that the German time bombs were unsuitable for use — their fuses made a low hissing sound that would open them before firing.
As it turned out, the British managed to develop more successful bombs of this type. Before the explosion, they did not unmask themselves and did not make any noise. Abwehr had several similar bombs at his disposal, it was they who were turned over to the conspirators. Trapping Hitler, who was suspicious of most of his own generals, was not an easy task. However, Treskov managed to persuade his old friend, General Schmundt, the then adjutant of the Fuhrer, to "process" his boss. After hesitations, Hitler nevertheless agreed to visit Russia, while Schmundt himself did not know anything about the plotting being prepared.
Twice - in the afternoon and evening of March 13 1943 - after Hitler arrived in Smolensk, two conspirator officers were ready to give in to the temptation to change the plan and detonate the bomb: first in the office in which the Führer spoke with the generals of the army group, and later in the officers' cafeteria, where dinner was arranged for all of them. However, they considered that this would lead to the death of the very generals who, freed from the oath of allegiance to Hitler, would have to assist the conspirators in seizing power in the country.

Fabian Schlabrendorf
At the same time, there was one more problem - how exactly to carry the bomb on Hitler's plane. As a result, Schlabrendorf collected two explosive devices, wrapping them in such a way that they looked like two bottles of brandy. During lunch, Treskov asked Colonel Heinz Brandt, who was among those accompanying the Fuhrer, to bring a couple of bottles of brandy as a gift for Treskov's old friend, General Helmut Stief, who was head of the organizational department of the ground forces command. Brandt, who knew nothing about the plot, said he would be happy to fulfill the request of the general. Already at the airport Shlabrendorf activated the delayed-action mechanism, after which he handed a deadly gift to Brandt, who entered Hitler's plane.
The explosive device prepared by the conspirators had a clockwork. After Schlabrendorf pressed the button, she crushed a small ampoule with a chemical solution, which was supposed to corrode the wire holding the spring. After the wire broke, the spring straightened and hit the striker, and he, in turn, the detonator of the bomb. According to calculations, the explosion in the plane was supposed to happen at the moment when Hitler flew Minsk, about half an hour after takeoff from the airport near Smolensk. Shivering with impatience, Schlabrendorf called to Berlin, warning other participants in the conspiracy that the Flash had begun. Holding his breath he and Treskov waited for the appearance of loud (in all meanings of the word) News.
They believed that the first news could be received on the radio from one of the fighters who accompanied Hitler’s aircraft and scored minutes. 20, 30, 40 have passed minutes, hours, but no news has been received. After more than two hours of waiting, they received a message that the Fuhrer's plane had successfully landed at Rustenburg. After receiving this news, Shlabrendorf immediately called the capital of Germany, conditionally saying that the assassination attempt on Hitler’s life had failed.
The position of the conspirators was serious. If they found a bomb in the plane, the investigation could have reached the organizers of the assassination, General Treskov, which would have caused the death of a wide circle of people - direct participants in the conspiracy. Fortunately, the bomb was not found. That same evening, Treskov phoned Colonel Brandt and, among other things, inquired whether he had time to hand over the bundle to General Stief. Brandt said he had no time for that yet. After that, Treskov asked him not to worry, because the wrong brandy was not in the bottles. He assured the colonel that tomorrow Schlabrendorf would come to him on business, who would also take with him a truly excellent cognac, which he was going to actually pass on to his friend.
Shlabrendorf, who went to Hitler’s headquarters, exchanged a couple of bottles of real cognac for a bomb. Then he sat in the night train to Berlin and locked himself in a compartment, where he dismantled a bundle disguised as brandy bottles. He found out that the mechanism worked: a small ampoule was crushed, the liquid really broke the wire, the striker struck the cap, but for some reason the detonator did not ignite. There is a version that the bomb did not work due to too low air temperature in the luggage compartment of the aircraft. Thus, Hitler was saved by a prolonged Russian winter, or by General Moroz, who was so unloved by German top officers.
After the failed assassination attempt with a bomb planted on Hitler's plane, Treskov did not leave the idea of an attempt on the Fuhrer. The conspirators prepared the next assassination attempt on 21 March 1943, when Hitler, accompanied by Goering, Himmler and Keitel, was to be present in Tahighaus in Berlin to commemorate the fallen heroes. The program of the event was a visit to the exhibition with the captured Soviet military equipment. The perpetrator of the assassination was the aristocrat from Silesia, Colonel Rudolf-Christoph von Gersdorf, who is one of the closest associates of Treskov. He was ready to sacrifice himself, undermining himself with the Führer. But here, too, Hitler was lucky; he practically ran through the exhibition in a few minutes, instead of the minutes allotted for the 30 program. At the same time, the chemical detonators of the bombs that Gersdorf carried were able to trigger at least 10 minutes after their activation. Gersdorf himself barely managed to extract the fuses already activated by him, hiding in the toilet.
Treskov was directly related to the July 20 Conspiracy. His relationship with the conspirators was extensive - he directly communicated with Colonel Count Klaus Schenk von Stauffffenberg one of the main developers of the conspiracy and the direct perpetrator of the attempted assassination of Hitler in his Wolfsschanger bet. With him, Treskov met while serving on the Eastern Front. Therefore, having learned about the failure of 20’s anti-Hitler attacks on July 1944, and realizing the inevitability of his arrest, von Treskov decided to commit suicide. And he tried to disguise him, imitating death in battle, to save his family members from persecution.
21 July 1944, he went to the front line, went into the neutral zone, where he used a gun to imitate a fight, and then blew himself up with a hand grenade. Initially, the remains of the general were buried in his homeland, however, when his role in the conspiracy was uncovered, they were exhumed and burned in the crematorium of the Sachsenhausen concentration camp, and the relatives of Treskov were repressed. In modern Germany, Major-General Henning von Treskov is considered one of the heroes of anti-Nazi resistance.
Information sources:
http://www.istpravda.ru/digest/2754
http://oursociety.ru/publ/novaja_i_novejshaja_istorija/khranimyj_djavolom_istorija_pokushenij_na_adolfa_gitlera/9-1-0-178
https://www.inopressa.ru/article/13mar2018/spiegel/hitler.html
Open source materials