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.

In the evening of the 9th November 1989, the East German government opened the Berlin Wall after central committee spokesman Guenter Schabowski mistakenly announced that GDR citizens could cross into West Berlin with immediate effect. Surprised border guards, who had been given no information about the new rules, were overwhelmed by the appearance of thousands of East Germans who wanted to cross. Although the border remained closed for around three hours, by 11pm the checkpoint at Bornholmer Strasse had been opened. Others followed soon after.

Communist Hungary had opened its Austrian border in September, which had encouraged East Germans to push for reform in their own country. Eventually, the weekly ‘Monday protests’ that attracted hundreds of thousands of people forced the government to prepare the new travel policy.

Although the new policy had been agreed by the Politburo on the afternoon of the 9th November, their intention was to implement the policy the next day so that border guards could be briefed and crossings managed in a controlled manner. However, Schabowski had not been at the Politburo meeting and so was only able to base his announcement on notes from a piece of paper handed to him shortly before the press conference. This explains his mistake over the timing of its introduction.

The announcement led huge crowds to begin gathering at the checkpoints, with thousands pouring through the border after the guards finally relented. Ironically, West Berliners still had to have a visa in order to cross to the East. Therefore, for a few weeks after the Wall was opened, East Berliners actually had greater freedom of movement than Westerners.

On the 7th November 1917, Red Guards entered the Winter Palace in St Petersburg in a defining event of the Bolshevik Revolution. Sometimes referred to as the October Revolution, the 7th November is the date from the modern Gregorian calendar that aligns with the 25th October on the old style Julian calendar, from which the revolution got its alternative name.

On the night of the 6th November Leon Trotsky led the Red Guards to take control of key government buildings and communication points such as post offices, bridges and the State Bank. Although the Red Guards were armed, historians generally accept that the takeover was carried out without bloodshed or indeed any shots being fired.

Throughout the 7th November large crowds of troops sympathetic to the Bolsheviks began to surround the Winter Palace. The actual attack on the palace began after a signal shot fired from cruiser ship Aurora. Soviet accounts of the night, portrayed most powerfully in Sergei Eisenstein’s film reenactment, present the takeover of the Winter Palace as a huge battle. However, this popular image is a fabrication. The large number of Red Guards marching towards the palace led to the Cossacks guarding the palace to desert their posts, while the remaining Cadets and volunteers from the Women’s Battalion laid down their weapons and surrendered after the Red Guards found their way inside the palace through an open door.

The remnants of the Provisional Government were discovered in a small dining room and arrested. Meanwhile the wine cellar was looted, leading to what historian Orlando Figes suggested was perhaps, “the biggest hangover in history”.

The Chinese Communists in the People’s Liberation Army had been fighting the second stage of a long and costly civil war against the Nationalist forces of Chiang Kai-shek, known as the Kuomintang, since shortly after the end of the Second World War. The first stage had been suspended in 1937 in order to focus a combined Chinese army against the Japanese, but relations between the two Chinese contingents had remained poor.

Even before the Japanese surrender, the Kuomintang and the PLA had begun to receive support from the USA and the USSR respectively. In the aftermath of the Second World War this division continued until the two Chinese armies resumed full-scale war on 26 June 1946. A quarter of China’s land area and a third of the population were already under Communist control, and the PLA soon expanded to over 1.2 million troops supported by a militia of almost double that.

With the resumption of the Civil War, the Communist Party itself promised land reform to the peasantry. In return for supporting the PLA, peasants were told that they would be given possession of their own land instead of needing to rent it from unscrupulous landlords. This secured more support for the Communists and, combined with the effective ‘passive defense’ strategy, led to the gradual expansion of Communist control and a Kuomintang retreat.

By October 1949 almost all of mainland China was under Communist control and Mao Zedong declared the foundation of the People’s Republic of China. Chiang Kai-shek and the retreating Kuomintang fled to the island of Taiwan in December.

On the 24th September 1946, Clark Clifford and George Elsey presented a report to President Truman in which they recommended “restraining and confining” Soviet influence. The report helped to shape Truman’s decision to follow a policy of containment, having a direct impact on the introduction of the Truman Doctrine and the Marshall Plan, and on the formation of NATO.

The report was a detailed appraisal of relations between the USA and the Soviet Union, elaborating on the points raised in the so-called “Long Telegram” by George F. Kennan at the U.S. Embassy in Moscow. Kennan’s telegram highlighted the USSR’s ‘perpetual war’ with capitalism, stating that the communist and capitalist worlds could never peacefully coexist.

These warnings were picked up by Clifford and Elsey, who also noted Kennan’s comments regarding the likelihood that the Soviets would back down from any direct conflict in their attempts to expand communism. Consequently they recommended “restraining and confining” Soviet influence in an attempt to maintain some form of coexistence. Elsey noted that the USSR needed to be persuaded that the USA was “too strong to be beaten and too determined to be frightened”. The term ‘containment’ was first used to describe this approach in an expanded essay in the Foreign Affairs journal.

Ten copies of the report were printed, the first of which was presented to the President. Truman’s daughter, Margaret, wrote that – having stayed up most of the night to read it – he ordered all copies to be brought to him and locked away since the content was a serious threat to US-Soviet relations.

On the 30th August 1918, Bolshevik leader Vladimir Ilyich Ulyanov – better known as Lenin – was the victim of a failed assassination plot. Fanya Kaplan, a member of the anti-Bolshevik faction of the Socialist Revolutionary Party, believed that Lenin was a ‘traitor to the revolution’ for dissolving the Constituent Assembly and banning other left-wing political parties. She fired three shots at him as he left the Hammer and Sickle factory in Moscow, of which one hit his arm and lodged in his shoulder while the other went through his neck and is reported to have punctured part of his left lung.

Made unconscious by the attack, Lenin was taken to his living quarters in the Kremlin from where he refused to move in case other would-be assassins attacked him. Without the medical facilities of a hospital, his doctors were unable to remove the bullets and, although Lenin did survive, the injuries he sustained may have contributed towards the strokes that led to his death in 1924.

In retaliation for the attack on Lenin barely two weeks after the successful assassination of Moisei Uritsky, the head of the Cheka in Petrograd, the Bolsheviks issued a decree beginning the Red Terror. Designed to crush counter-revolutionary action against the Bolsheviks, the Red Terror is generally accepted to have lasted throughout the period of the Civil War until 1922. Meanwhile, the Communist Party newspaper Pravda used the attack as a propaganda tool to promote Lenin.

Kaplan was executed on the 3rd September, but over the next four years tens if not hundreds of thousands of Bolsheviks opponents were killed.

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.

At around 11pm on the 20th August 1968, troops from the USSR, Bulgaria, Poland and Hungary entered Czechoslovakia in an invasion that brought the Prague Spring to an end. The invasion, known as Operation Danube, led to almost half a million soldiers crossing the border to bring Alexander Dubček’s reforms to an end.

The Prague Spring began in early January, shortly after Dubček became the leader of Czechoslovakia. Keen to push forward with de-Stalinisation within the country, he granted greater freedom to the press and introduced a programme of ‘socialism with a human face’ by which he intended to decentralise parts the economy and introduce some limited democratic reforms.

This new openness saw open criticisms of the Czechoslovakian government begin to appear in the press, which concerned the other Warsaw Pact countries. János Kádár, the leader of Hungary who came to power after the fall of Imre Nagy in 1956, even warned that the situation in Czechoslovakia seemed “similar to the prologue of the Hungarian counterrevolution”.

Concerned that Dubček’s reforms might spread to other Eastern Bloc countries and threaten the USSR’s security, the Soviet leader Brezhnev chose to open negotiations with the Czechoslovakian leadership that lasted into August. The talks ended in compromise, but Brezhnev continued to be unhappy with the situation and began to prepare military intervention.

Overwhelmed by the military invasion, Dubček asked his people not to resist. 72 Czech and Slovak soldiers and 108 civilians were killed, with a further 500 civilians injured. It later emerged that members of the Czechoslovakian government had asked for Soviet assistance against Dubček’s reforms.

On the 14th August 1980, workers at the Lenin Shipyard in the Polish city of Gdańsk led by electrician Lech Wałęsa began a strike that led to the formation of the Solidarity labour movement. A decade of economic and political crises preceded the 1980 strike, but the Gdańsk strike spread throughout Poland and galvanised various other strike committees to join together for a common goal.

The trigger for the strike was the firing of a popular worker at the shipyard, a female crane operator and activist called Anna Walentynowicz. Just 5 months before her planned retirement, she was sacked for being a member of an illegal trade union. This move proved highly unpopular with the shipyard workforce, who demanded that she be reinstated.

Just a week after beginning the strike a governmental commission began negotiations with the strikers and, on the 30th August, they and representatives of the Gdańsk workers signed an agreement in which many of the strikers’ demands were met. The fact that political change, including the resignation of the Polish Communist Party’s General Secretary, had come from the workers’ action emboldened the people of Poland and fuelled the formation of the national labour union Solidarity.

Within two years up to 80% of the entire Polish workforce had joined Solidarity or one of its suborganisations, and they continued to use strikes to achieve political change. In March 1981, the crippling effects of 12 million people going on a four-hour warning strike demonstrated that the Communist Party was no longer the most powerful force in the country.

Beginning at midnight on the 13th August 1961, East German police and army began to close the border with West Berlin. The barbed wire and mesh barrier that was constructed overnight was gradually replaced with a virtually impregnable ring of reinforced concrete that ran 155km around West Berlin.

The border between East and West Germany – sometimes referred to as the inner-German border – had been closed since 1952, although the crossing between East and West Berlin remained open. This easy access proved highly problematic for the Communist government of East Germany, since people comparing the two parts of the city found West Berlin to be much more appealing.

Berlin became a focal point for East Germans who wanted to move to the West, and by 1961 an estimated 20% of the entire population had emigrated. The majority were young, educated, and skilled professionals. This so-called “brain drain” seriously depleted the workforce, and was hugely damaging to the political credibility of East Germany.

The erection of the Berlin Wall was intended to put a stop both of these problems, although it was presented to the East German people as the “Anti-Fascist Protection Rampart”. The East German leader, Walter Ulbricht, had even denied any intention of building a wall just two months earlier despite pressuring USSR Premier Nikita Khrushchev to support him doing just that.

The construction of the Wall turned Berlin overnight from the easiest way to cross between East and West into the most difficult. It cut people off from their jobs, and divided families. The crossing was not opened again for 28 years.