At the end of June 1914, few Americans paid attention to a story in newspapers about the assassination of the heir to the Austrian-Hungary throne in the Serbian capital of Sarajevo. The Austrians demanded satisfaction from the Serbians with an ultimatum. Germany backed Austria, Russia supported their fellow Slavs in Serbia, and France and Great Britain became involved because of secret treaties tying them to Russia. Virtually all European countries mobilized their armies and the continent was at war within weeks.
People who were familiar with the European situation were not surprised at war breaking out. The nineteenth century saw different European countries at each other’s throats over the “Dark Continent,” Africa. Explorers from Great Britain, Germany, France, and Belgium were uncovering mineral riches in the interior, while the British already had footprints in South Africa and North Africa in the Nile watershed; and of course, their lifeline to India, the Suez Canal.
Furthermore, smaller wars were fought by the European powers over the two decades prior to the Great War. Britain fought an unpopular war with the Boers in South Africa. Spain lost its war with the United States in Cuba and the Philippines. Russia was beaten by Japan in the far east. The Ottoman empire (i.e. Turkey) was collapsing: the Balkan League had driven the Turks from the Balkan Peninsula. In other words, all of the continent was an armed camp, waiting for an excuse to mobilize.
Meanwhile, Germany and Great Britain engaged in an arms race at sea. Queen Victoria was aging while her nation was aggressively building war ships to compete with Germany, governed by her grandson, Emperor Wilhelm. In Russia, another grandson, Nicholas was Tsar. The coming war pitted the late Victoria’s grandchildren against each other. George V of Great Britain and Tzar Nicholas were on the same side, Wilhelm on the other. Unfortunately, Nicholas and his family were killed by the Bolsheviks during the Russian Revolution, after Russia withdrew from the war in 1917.
At the opening of the war, the Germans planned to invade France through Belgium and get the French out the way before British could intervene. But the invaders were stopped short of Paris, by re-enforcements brought by taxis from the capital. Then, bolstered by the British Expeditionary Force (BEF) the French counter-attacked. The ensuing Battle of Marne pushed the Germans back to the Aisne River, where both sides dug a intricate series of trenches that lasted till the end of the war.
Like in the American Civil War, commanders took time to develop different tactics to deal with new weapons. Going “over the top,” out of trenches, against machine gun fire was suicidal as much as Civil War soldiers charging against emplaced troops with rifles was fruitless and deadly. Tanks with heavy armor replaced cavalry, although some countries continued to use horse borne soldiers into World War II. Armored piercing shells was answer to tanks. Gas was another new weapon both sides used against their enemies in spite being forbad by treaties. Bombing from the air, first from dirigibles, later from planes made targets of civilians , although not with the frequency of the Second World War. Most deaths and injuries on the battlefield came from artillery shelling. At sea, submarines could sink surface ships with no warning. Unlike earlier wars, where most fatalities were caused by disease, this time most military deaths came from combat.
Run up to WWI:
Blom, Phillipp. The Vertigo Years: Europe, 1900-1914.
Robert F. Massie. Dreadnought: Great Britain, Germany, and the Coming of the Great War.
Barbara Tuchman. The Proud Tower: a portrait of the world before the war, 1890-1914.
Niall Ferguson. The Pity of War: Explaining World War I
Paul Fussel. The Great War and Modern Memory.
Martin Gilbert. World War I .
Adam Hochschild. To End All Wars: A Story of Loyalty and Rebellion.
John Keegan. World War I.
Jay Winter and Blaine Baggett. The Great War and the Shaping of the 20th Century
Opening of the War:
Max Hastings. Catastrophe 1914: Europe Goes to War.
Barbara Tuchman. Guns of August.