Armistice that ends World War I: Collapse of the Second Reich, cession of Alsace-Lorraine and subsequent French occupation of the Ruhr; Collapse of the Austro-Hungarian Empire (Austria, Hungary, Czechoslovakia, Yugoslavia are created and Romania expands); Collapse of the Byzantine Empire which is divided between France (Syria and Lebanon) and England (Palestine and Mesopotamia) World War I: 9 to 12 million deaths (uncertainty is given by Russian casualties: 5 to 8 million) – 116,516 American victims – 65 million people involved in 18 countries – Cost: 2.85 trillion US dollars

Marshal Diaz proclaims Italy’s victory in the conflict with the Austro-Hungarians in the First World War

Italian troops enter Trento and Trieste. Armistice between Italy and Austria-Hungary at Villa Giusti, near Padua.

Austrian retreat: the Second Battle of the Piave ends; 34,000 Austrians and 90,000 Italians remain on the field, 24,500 Austrians are taken prisoner and 100,000 are wounded.

Ernst Fetterlein, the Tsar’s codebreaker, who fled Russia after the October Revolution, was hired by the British secret service (SIS, now MI6) to work on Bolshevik codes.

Second Battle of the Piave: 60 Austrian and 56 Italian divisions face each other

Soviet Union. Mensheviks (real or alleged) are expelled from all soviets, and then many are arrested. Other streams of people are sent to the gulags: anarchists, pro-Cadet (scientists, academics, artists, writers, engineers, etc.), and the Muzhik kulaks. The overall plan “is not to wage war on individuals, but to exterminate the bourgeoisie as a class,” and conspiracies are everywhere, and to capture those who plot, entire social classes are sent to the gulags.

Austrian mine under the Italian Dente on Pasubio: 50,000 kg of explosives (0.05 kton): the largest mine ever detonated in this sector

Cryptographers in various countries began experimenting with long, unstructured cryptographic keys (random keys—a long sequence of random numbers spanning hundreds of sheets of paper) and with one-time pad cyphers, cryptographic keys that were destroyed after use and never used again. In some ways, this was a holy grail for cryptographers, as it was an absolutely secure system. Indeed, if it were possible to test all possible keys, the true message would be revealed, along with several false positives. However, one-time pad cyphers were almost never used, due to their impracticality on the battlefield and in general, due to the enormous quantity of papers that had to be delivered somehow, without risking them falling into enemy hands. A curious fact, however, is that in some cases, where communications are rare and cost is irrelevant, the one-time pad cypher is still used: this is the hotline between the American and Russian (formerly Soviet) governments.

The Germans introduced the ADFGVX encryption cipher just before the offensive they were about to begin on March 21st. Conceptually, it was nothing new, but “just” very complex, a mix of numerous substitutions and transpositions. The Allies, however, had an ace up their sleeve: the French cryptanalyst Georges Painvin, who managed to break the German code on June 2nd, not in time for the late March offensive, but in time for the next one, whose outcome would be largely determined by the clear reading of German messages. Also in 1918, cryptographers from various countries began experimenting with long, unstructured cryptographic keys (random keys—a long sequence of random numbers spanning hundreds of sheets of paper) and with one-time pad cyphers, i.e., cryptographic keys that were destroyed after use and never used again. In some ways, it’s a holy grail for cryptographers, as it’s an absolutely secure system. Indeed, if it were possible to test all possible keys, the true message would be revealed, along with several false positives. However, the one-time pad cypher was almost never used, due to its impracticality on the battlefield and in general, due to the enormous quantity of documents that had to be delivered somehow, without risking them falling into enemy hands. Curiously, however, in some cases, where communications are rare and cost is irrelevant, the one-time pad cypher is still used: this is the hotline between the American and Russian (formerly Soviet) governments.

Russia signs a separate peace. Revolutionary Russia signs the Treaty of Brest-Litovsk with the Central Powers, seceding from its Allies and granting independence to Polish and Baltic territories, Ukraine, and Finland. Russia’s disastrous participation in World War I had contributed to the success of the Bolshevik Revolution of November 1917. The following December, Germany agreed to an armistice and began peace talks with Russia. Lenin sent Trotsky to the negotiating table in Brest-Litovsk, Belarus. The talks failed when Germany demanded independence for Russia’s territories in Eastern Europe, and in February 1918, fighting on the Eastern Front resumed. As the Germans advanced toward St. Petersburg, Lenin authorized the conclusion of the Treaty of Brest-Litovsk on March 3, 1918. The Germans thus hoped to gain dominion over Russian territories, but in November 1918 an armistice ended World War I, condemning Germany to demilitarization and Allied domination. In 1919, during the Russian Civil War, the Soviets retook Ukraine, in 1939 they occupied part of Poland, and in 1940 the Baltic countries, after signing a non-belligerence pact with the Germans.

Berlin. Approximately half of children suffer from some form of rickets, a childhood disease characterized by weakening of the bones. The causes are unclear, but it is more common among the poorest and most malnourished children due to the hardships of the Great War. A German doctor, Kurt Huldschinsky, discovers that subjecting children to ultraviolet light therapy produces significant improvements. It will later be discovered that vitamin D improves bone development.

The French Gaston Julia and Pierre Fatou discovered the fractal figures later called Julia Sets: the colored points (inside the prisoner set) if subjected to the z2+c transformation remain confined in the prisoner set, the points outside it diverge to infinity.

Italian victory of Vittorio Veneto

Austrian mine against the Italian Dente on Pasubio

(October 25 in the Russian calendar) The cruiser Aurora shells the Winter Palace in St. Petersburg: the Russian Revolution begins.

Second Italian mine on the Marmolada glacier