The Battle of Berlin ended after German General Helmuth Weidling surrendered to Soviet General Vasily Chuikov.

Determined to capture Berlin before the Western Allies, Stalin’s generals began their assault on the defensive line of the Oder and Neisse rivers on the morning of 16 April. 2 million German civilians and no more than 200,000 German soldiers were in and around Berlin when the USSR broke through the defences having suffered casualties in the tens of thousands.

Travelling at up to 30-40km a day, the first Red Army troops reached Berlin in time for Hitler’s 56th birthday on 20 April. Artillery began bombarding the city and didn’t cease until the surrender almost two weeks later. Meanwhile other Soviet units encircled the city leading to Hitler, who was based in the Führerbunker, angrily declaring that the war was lost. Nevertheless he appointed General Weidling to command the Berlin Defence Area with a force of 45,000 soldiers supported by police officers, members of the Hitler Youth, and the Volkssturm militia.

By 30 April Soviet troops had reached the Reichstag and, late that evening, successfully placed a flag on top that was removed the following morning by German defenders. The building was finally taken over on 2 May and a new flag was raised, of which an iconic photograph was taken. General Weidling and his staff surrendered the same morning having failed to negotiate a conditional surrender.

Following the surrender the Soviets sought to restore essential services and provide food to the German survivors. However, some troops who reached the city lacked the discipline of the first echelon and committed shocking crimes against Berliners including rape, pillage and murder.

Shortly after midnight on the 25th February 1956, Soviet leader Nikita Khrushchev delivered his ‘secret speech’, officially called “On the Cult of Personality and Its Consequences”, in a four hour “closed session” at the end of the 20th Party Congress of the Communist Party of the Soviet Union. Laying the foundation for his wide-reaching de-Stalinisation campaign, the speech was a vehement denunciation of Stalin’s abuses of power and his creation of a personality cult.

Khrushchev’s speech signalled a dramatic reversal of Soviet policy, which he said had come about due to Stalin’s misinterpretation or misrepresentation of Marxist-Leninist doctrine. The ‘secret speech’ allowed Khrushchev to distance himself from the worst crimes of the Stalin’s rule, even though he himself had been responsible for thousands of deaths during his rule.  Additionally, and of great significance for the West, Khrushchev also advocated a policy of “peaceful coexistence” rather than continue Stalin’s policy of preparing for an inevitable war.

Although the full details of the speech were only supposed to reach the public gradually, rumours of its contents spread quickly. Israeli intelligence officers finally obtained a full copy of the speech, and passed it to the United States government, who leaked it to the press at the start of June. Although Khrushchev had, by this point, begun to implement de-Stalinisation the printing of the speech in the New York Times on the 5th June dictated demands for a faster pace of change in Eastern Europe. Large-scale change was, however, still slow. Although Poland’s government granted some concessions in October, the situation in Hungary ended very differently.

On the 14th January 1943, the Casablanca Conference began in Morocco. Primarily a military meeting between the USA and Britain, the conference resulted in a declaration of the doctrine of “unconditional surrender”.

The conference saw the Combined Chiefs of Staff join American President Franklin D. Roosevelt and British Prime Minister Winston Churchill to discuss the future strategy for fighting the Second World War. Representing the Free French forces, Generals Charles de Gaulle, and Henri Giraud were also in attendance. Roosevelt’s attendance at the conference marked the first time a President had left American soil during wartime. Meanwhile the Soviet leader Joseph Stalin declined his invitation as he felt his presence was needed at home during the ongoing Battle of Stalingrad.

The conference saw the leaders agree to invade Sicily after the North African Campaign, as a way to pull Axis forces away from mainland Europe and weaken the German defence ahead of a later Allied invasion of France. In return, Churchill agreed to send more troops to the Pacific in order to help the American forces continue their fight against the Japanese. Meanwhile, they agreed to launch combined bombing missions against Germany and to destroy German U-boats in the Atlantic.

Details of the conference were kept from the public until the participants left Casablanca. However, a number of journalists were invited for a press conference on the 24th January where vague details of the discussions were announced by Roosevelt. He did, however, announce his demand for the unconditional surrender of the Axis powers – an approach that had been discussed at the conference, but was not fully embraced by Churchill.

Trotsky had been a key figure in the Bolshevik Revolution of 1917. He soon became one of the members of the first Politburo that was founded to manage the transition to a communist state, alongside the Bolshevik founder Vladimir Lenin, and the USSR’s future leader Joseph Stalin.

As Lenin’s health began to fail in the early 1920s, it initially appeared as though Trotsky would be his successor. Following Stalin’s alliance with Zinoviev and Kamenev in the troika, however, Trotsky soon found himself marginalised and he became the subject of rumours about his health and capability to serve in government.

Stalin subsequently emerged as the leader of the USSR following Lenin’s death in 1924. Trotsky’s Left Opposition faction was a vocal critic of many of Stalin’s policies but, with Trotsky himself being increasingly side-lined from government decisions, he was removed from his position as war commissar in 1925 and from the Politburo itself the following year.

Having organised a demonstration by the Left Opposition to celebrate the tenth anniversary of the Bolshevik Revolution, Trotsky was accused of fomenting and organising a counter revolution. He, along with his recent ally Zinoviev, was expelled from the Communist Party on 12 November 1927 while 98 of his supporters met the same fate a month later.

Trotsky was soon exiled to Alma Ata, a small town in Kazakhstan, but within a year had left the USSR completely. He never returned, eventually being granted asylum in Mexico where he was assassinated with an ice pick by an NKVD agent.

On the 29th August 1949, the Soviet Union successfully detonated its first nuclear weapon codenamed RDS-1 and nicknamed First Lightning. The explosion had the power of 22 kilotons of TNT, and was 50% more destructive than its designers had expected.

The USSR started its nuclear program in 1943 after discovering the USA, Britain and Canada had begun bomb development. Assisted by intelligence from sources inside the USA’s Manhattan Project, the Soviet Union’s program developed quickly as the Soviets were able to replicate American successes while avoiding some of their costlier mistakes. Consequently, although the majority of Cold War academics accept that the USSR’s success had a lot to do with domestic expertise they recognise that intelligence helped to reduce the time it took for them to develop the bomb.

Work was accelerated after the bombings of Hiroshima and Nagasaki in secret, purpose-built cities dedicated to the nuclear program known as Atomgrads. By 1949 the Soviets had developed two types of bomb, but opted to detonate the simpler of the two designs first since it was similar in design to the successful Fat Man bomb that was dropped on Nagasaki.

The RDS-1 test was conducted in secret in an attempt to avoid the USA increasing its own nuclear program, but the US Air Force began to detect radioactive fallout from the explosion a few days later and tracked the trail. Soviet success had occurred up to 4 years ahead of Western estimates, and the knowledge that the USSR now had ‘the bomb’ dramatically increased tensions in the early years of the Cold War.

On May 12th 1949, the Soviet Union ended its blockade of West Berlin.  Instigated on the 24th June the previous year, the blockade prevented all rail, road, and water transport between Berlin and the West of the Germany.

Germany had been divided into four parts at the end of World War 2 with Britain, France, the USA and the USSR each administering one area.  Buried deep in the Soviet zone, the Berlin was also divided into four sectors.  It was to the area controlled by the Western powers that the USSR blocked access.

Faced with the possibility of all-out war if they forced their way through the blockade, the Americans opted to make use of the three air corridors that provided unrestricted aerial access to Berlin.  The USSR knew it risked war if it shot down any aircraft, and was therefore powerless to stop them.  Launched four days after the blockade, the Berlin Airlift went on to see over 200,000 individual flights transport up to 8,500 tons of supplies each day.

The pilots and ground crews soon settled into an efficient rhythm.  An unusually short winter also helped to keep the airlift running.  By the spring of 1949 it was clear that the Western powers had achieved the impossible by supplying West Berlin by air alone.  On the 15th April the USSR expressed a willingness to end the blockade and, after a period of negotiation, it was lifted at one minute past midnight on 12 May 1949.  The blockade was over, but the Cold War had just begun.

Pravda, the official newspaper of what became the Communist Party of the Soviet Union, was first published.

Prior to the foundation of the CPSU many revolutionary socialists belonged to the Russian Social Democratic Labour Party. It was the RSDLP that had originally split into Bolshevik (majority) and Menshevik (minority) factions in 1903.

An early version of Pravda appeared that year, although at the time it was a journal without political affiliation. Its editorial board gradually began to include active members of the RSDLP and, by 1909 when its headquarters moved to Vienna, the board was dominated by Bolsheviks under the editorship of Leon Trotsky.

The Central Committee of the RSDLP had first suggested making Pravda its official mouthpiece in 1910, but it wasn’t until the Mensheviks were expelled from the party in January 1912 that this happened. The Bolshevik leader Vladimir Lenin moved the paper to St Petersburg and the first edition was published on 5 May, the anniversary of Karl Marx’s birth.

The first edition of the newspaper consisted of just four pages, and focused on workers’ issues. As its circulation increased to as many as 60,000 copies by July 1914, Pravda was shut down by the tsarist government censors.

Despite this suppression, Pravda continued to be printed under a serious of pseudonyms. The newspaper formally reopened following the February Revolution of 1917 and by 15 March it was being co-edited by Joseph Stalin following his return from exile.

Pravda remained the official newspaper of the Soviet Communist Party until it was abolished in 1991. The newspaper continues to exist, albeit not as a daily publication.

On the 4th February 1945 the Yalta Conference began. Attended by the “Big Three” Allied leaders, the conference saw United States President Franklin D. Roosevelt, British Prime Minister Winston Churchill and Soviet Premier Joseph Stalin meet to discuss the government of post-war Europe.

The three leaders had previously met at the Tehran Conference in 1943 where they set out a unified military strategy, but at Yalta the focus was exclusively on the end of the war and its aftermath. It was clear that the war in Europe was in its final stages, so they agreed to demand Germany’s unconditional surrender after which the country – and Berlin – would be split into four zones of occupation. Germany was to undergo a process of demilitarization and denazification, and Nazi war criminals were to be hunted down and brought to justice.

Furthermore, the three allies considered the fate of Eastern European countries that had been under Nazi occupation. Poland was the focus of much of the discussion, but the agreement reached was intended to apply to every country. The Protocol of Proceedings stated that the allies would assist the liberated countries to form “interim governmental authorities broadly representative of all democratic elements in the population…and the earliest possible establishment through free elections of governments responsive to the will of the people.”

The terms of the agreement, when they were made public, were met with harsh criticism in Britain and the United States. Some of these criticisms came to be justified when, at the end of the war, the Soviet Union installed communist governments throughout Eastern Europe.

On the 30th December 1922, the USSR – the Union of Soviet Socialist Republics – was founded. The Treaty on the Creation of the USSR and the Declaration of the Creation of the USSR, which were approved by delegations from the founding countries on the 29th December, formed the constitutional basis for the Soviet Union. However, they didn’t officially come into force until the 30th when they were confirmed by the 1st Congress of Soviets and signed by the heads of each republic’s respective delegation.

The Soviet Union in 1922 consisted of just four Soviet republics – the Russian SFSR, Ukrainian SSR, Byelorussian SSR and Transcaucasian SFSR – although it’s important to note that the Russian and Transcaucasian SFSRs actually incorporated a number of separate Soviet Socialist Republics. The creation of the USSR therefore effectively created a centralised federal government.

This was an important step for the Bolsheviks who, having won the Russian Civil War, needed to consolidate their gains into a formal political entity. Stalin in particular argued that the New Economic Policy that followed war communism required centralised control, which threatened some national groups. At the same time, some Bolsheviks hoped for a world revolution that would overthrow capitalist governments around the globe.

The USSR’s founding documents therefore allowed Soviet republics to withdraw from the Union at any time, even though none of them actually did so before the collapse of the Soviet Union in 1991. Similarly new members were able to join the union at any time, which meant that by 1940 the USSR’s membership had grown from four republics in 1922 to 16.

On the 1st October 1928, the Soviet Union introduced Joseph Stalin’s first five-year plan. The plan set a series of economic goals to be achieved between 1929 and 1934, with the intention of rapidly industrialising the country in case of war with the West. Based on Stalin’s policy of Socialism in One Country, the five-year plan called for a complete change in the culture of the Soviet Union that affected agriculture just as much as industry.

A vital ingredient in being able to fulfil the industrial goals of the five-year plan was increasing agricultural productivity, since this would release peasants and farm labourers from the land and allow them to become industrial workers. The first five-year plan is therefore probably most famous for the introduction of the policy of collectivisation, where hundreds of peasants were put together to work on enormous farms that covered thousands of acres.

The dramatic increase in food output per peasant as a result of mechanisation on these farms freed up former agricultural workers to move to the new factories instead, with the number of industrial workers almost doubling between 1928 and the end of the plan in 1932. However, significant opposition to the process of collectivisation meant that overall productivity remained low in many areas and caused famines as Party officials seized food for the cities and left the agricultural workers with nothing.

In the factories, however, production soared. Although the targets were constantly revised to the point where the targets would never be achieved, the first five-year plan firmly set the USSR on the road to becoming a world superpower.