During the second half of the nineteenth century, the United States engaged in a massive railroad construction project. This linked communities over vast distances for the first time in American history. The First Transcontinental Railroad was built between 1863 and 1869 and finished in 1869, with the initial first destination being San Francisco.

The Emancipation Proclamation was issued in 1863, in the middle of the Civil War, by President Abraham Lincoln. The Proclamation formally stated that the slaves living in the territories currently in open rebellion were now and forever free.

The Balfour Declaration was published in 1917 and proposed to create a new nation for the Jewish people in the territory of Palestine. This nation would come to be called Israel. It represents a massive milestone in the Zionist movement to achieve an independent Jewish nation.

The Atlantic Charter was an agreement signed between the United States and Great Britain in 1941. It proposed the ideal manner in which the war and the post-war world should be conducted and shaped. It was later supported by the other allied powers and led to the creation of the United Nations.

In World War Two, the Axis Powers were Germany, Japan, and Italy. They fought against the Allied Powers of Britain, France, the United States, and the Soviet Union.

The Potsdam Conference took place in occupied Germany during the waning days of the Second World War. It was attended by all the Allied Powers, although focus tends to go towards President Truman, representing the United States, Josef Stalin, representing the Soviet Union, and Prime Ministers Winston Churchill and later Clement Attlee, representing Great Britain. The Allied Powers met to decide how to punish Germany and how to rebuild the world after the war.

The Triple Entente, entente meaning "friendship" in French, was cemented by the signing of the Anglo-Russian Entente in 1907. The French and Russians had already entered into an alliance in 1894, while the UK and Frace had put an end to centuries of imperial animosity in 1904. In addition to ending competition between the three constituent powers, the alliance that formed on the basis of the agreements provided for military cooperation as well. The Triple Entente also came about as a geo-political counterweight to the power wielded over Central Europe by the Triple Alliance of Germany, Austria-Hungary, and Italy. The web of alliances that spread over most of Europe has long been thought to have been one of the precipitating factors that led to the spread of war across the continent in WWI. 

The Russian Revolution took place in 1917 and witnessed the decline of the longstanding Russian monarchy to be replaced with a communist government. The primary cause for the Russian revolution was the extended suffering of the Russian people during World War One. The Russian Revolution caused Russia to withdraw from World War One and precipitated the rise of the Soviet Union.

Czar Nicholas II was the last monarch of Russia. When the Russian monarchy fell during the Russian Revolution of 1917, Nicholas and his family were executed. Czar Alexander II abolished serfdom and is therefore sometimes known as Alexander the Liberator. Josef Stalin presided over the Soviet war effort during World War Two.

The first leader of the Soviet Union, which began in 1922, was Vladimir Lenin. Lenin was one of the leaders of the Russian Revolution, in which the monarchy was overthrown and replaced with socialism. He would serve as leader of the Soviet Union until his death, when he was replaced by Josef Stalin. Stalin in turn would reign throughout the thirties and forties until his death led to the leadership of Nikita Khrushchev.