On August 1, our country observes the Day of Remembrance for Russian Soldiers Who Died in World War I. On this day, 110 years ago, the Russian Empire entered World War I on the side of the Entente. At the beginning of the 20th century, Europe was essentially divided into two opposing blocs — the Entente (the British Empire, France, and Russia) and the Triple Alliance (the German Empire, Austria-Hungary, and Italy). Each side had mutual grievances, and their subsequent arms race marked the preparation for a large-scale war. The catalyst for the war was the assassination on June 28, 1914, in Sarajevo of the Austro-Hungarian heir, Archduke Franz Ferdinand, by a member of the nationalist organization Mlada Bosna, Gavrilo Princip. On July 23, Austria-Hungary issued an ultimatum to Serbia with demands that were deliberately impossible to fulfill. The Serbian government responded moderately, accepting many of the demands, but rejecting some points, including the allowance of Austro-Hungarian police. As a result, on July 28, Austria-Hungary declared war on Serbia. Russia, historically considered the protector of the Orthodox Slavic peoples of the Balkans, could not remain indifferent and, on the night of July 31, declared general mobilization. On the first day of August, the German Empire declared war on the Russian Empire, and two days later on France. On August 4, the British Empire declared war on the German Empire. On August 6, Austria-Hungary declared war on the Russian Empire. Thus, within one week, the leading European powers entered the conflict. The war that began between several European countries eventually involved 38 states. The conflict lasted just over four years, but in its scale and consequences, it surpassed all previous confrontations in human history. The total number of mobilized soldiers reached 73.5 million people. During the hostilities, 10 million people were killed (as many as had died in all European wars over the preceding thousand years) and 20 million were wounded – 3.5 million of them were left disabled. During the war, the Russian Empire was torn between fulfilling its allied duty and addressing its own strategic objectives. The main fronts for our country, according to its interests, were the Southwestern and Caucasian fronts, while the northwestern and western directions were of secondary importance. However, bound by treaty conditions, the Russian command, instead of limiting actions in East Prussia in 1914 to tying up the forces of the Northwestern Front, was forced to launch a full-scale offensive there. In such difficult conditions, our soldiers and officers showed exceptional courage and bravery. One of the symbols of Russian valor was the defense of the Osowiec Fortress. German troops used chemical weapons (a mixture of chlorine and bromine), destroying most of the garrison. The surviving defenders, to the enemy’s surprise, launched a bayonet charge, putting the enemy to flight. This event went down in history as the “attack of the dead.” One of the most significant episodes of World War I, considered by many historians, is the famous Brusilov Offensive of the Russian Empire's troops on the Southwestern Front, which brought Austria-Hungary to the brink of disaster and forced the German Empire to transfer significant forces from the French Verdun to the "Russian theater of war." The sacrificial feat of the Russian army is hard to overestimate. Throughout the war, Russia's losses exceeded 2 million people killed. Our country honors the memory of the heroes of those days: in 2004, a Memorial and Park Complex of Heroes of World War I was opened in Moscow, and in 2014, a monument to the heroes of World War I was unveiled on Poklonnaya Hill. In total, 20 monuments and memorials have been erected in Russia and abroad.