Until a century ago, Karl Marx was an unpracticed intellectual, a prolix babbler who inspired followers and generated movements, but remained an ideal rather than a reality. Then came the Bolshevik Revolution. On November 7 (October 25 on the old Russian calendar), the Soviet Union was effectively born.

This event may have been as momentous as the war that spawned the first communist state. Upwards of twenty million died in World War I at the hands and guns of the combatants. However, the Soviet Union alone killed as many (and perhaps far more) people during its lifetime. Even more died in the People’s Republic of China. In the small Southeast Asian nation of Cambodia, briefly renamed Kampuchea, the radical communist leadership killed between 20 and 30 percent of the population. We continue to live with the consequences of Marxism today.

Life was good in 1914. The industrial revolution delivered entire populations from immiserating poverty. Globalization spread prosperity ever farther afield. Democracy remained limited and fragile, but liberal currents affected even the great autocracies of Austria-Hungary, Germany and Russia. All were evolving, however irregularly, into freer, more prosperous and better societies. The future beckoned.

But on June 28, Austria-Hungary’s Archduke Franz Ferdinand, heir to the venerable Hapsburg throne, and his wife Sophie were visiting Sarajevo in the recently annexed province of Bosnia. In a plot backed by Serbian military intelligence, the young Serbian nationalist Gavrilo Princip assassinated the pair, setting in motion diplomats and statesmen, generals and admirals, and armies and fleets around the globe.

Governments mobilized their militaries to the applause of their populations, who imagined glory and victory. Many on both sides predicted a quick triumph—a Russian princess gaily forecast, “There’s going to be war. There’ll be nothing left of Austria. . . . Our armies will meet in Berlin. Germany will be destroyed!” However, years of conflict ensued. Trench warfare on the western front created a human sausage grinder. The eastern front remained mobile, but also murderous: the population-rich Russian Empire substituted manpower for technology. Peasants died in a war started by aristocrats for reasons no one truly understood.

This was the central tragedy of the conflict. Before troops began marching in August 1914, common people’s lives were improving. Progress varied by nation and group, but even those at bottom in the great czarist despotism were doing better. Then came the continental war. Economic welfare was sacrificed by the various war machines; blockades, conquest and destruction wrecked once prosperous societies. Lives were sacrificed for no interest recognizable to those doing the fighting and dying. Just why were Germans, French, Britons, Russians, Austro-Hungarians, Serbs, Turks and others confronting each other on the battlefield?

Nowhere was the tragedy greater than in the mysterious, mystical, antiquated Russian Empire. Stretching from Europe to the Pacific, the vast country swallowed and destroyed Napoleon Bonaparte, Europe’s would-be conqueror, wrecking his imperial project. For a long time St. Petersburg was a force of conservatism, even reaction, opposed to Western liberalism and especially the French Revolution.

Germany’s “Iron Chancellor,” Otto von Bismarck, thought similarly while creating the new Prussian Empire. He forged the Dreikaiserbund, or Three Emperors’ League, which drew Germany together with its chief ally—Austria-Hungary—and Russia. Tensions between the latter two caused the arrangement to lapse in 1887, but Bismarck negotiated the Reinsurance Treaty with the czar, which provided for neutrality if either party ended up fighting Austria-Hungary or France. The pact ensured not just stability, but peace, by creating a firebreak to conflict in eastern Europe.

However, the young, bombastic, and unpredictable Kaiser Wilhelm II ascended to the throne and decided to take control. He ousted Bismarck and dropped the Reinsurance Treaty, assuming that Russia would never make common cause with the French Republic. However, the latter, anxious for revenge after losing a war and territory to Prussia in 1871, joined with St. Petersburg, which sought to dominate the Balkans to the detriment of Vienna. The new alliance effectively evolved into an offensive pact, since it would apply even if the treaty members instigated war.

But imperial Russia was a giant with feet of clay. In 1904 it lost an army, fleet and war to Japan in the Far East. Then popular unrest forced Czar Nicholas II to accept constitutional reform, including an elected State Duma. He lacked the intelligence and personality to stem the liberalizing currents; the regime staggered along unsteadily amid peace and prosperity.

Then came June 28, 1914. Russian officials probably knew of the Serbian plot against the archduke, which was an act of state terrorism. St. Petersburg nevertheless backed its small ally against Vienna, which was determined to destroy ethnic terrorists who threatened Habsburg rule. Austria-Hungary followed an ultimatum against Belgrade with a declaration of war, dragging in Russia, which defended Serbia; Germany, which backed Vienna; France, a treaty ally of St. Petersburg; and ultimately Great Britain, on Russia’s side as well. Other nations later joined Europe’s continental slaughterhouse.

Russian elites had various grievances against Germany, but none could justify war. In February 1914, former interior minister Pyotr Durnovo wrote a memorandum to the czar warning that in war St. Petersburg risked defeat, in which case the defeated army, the “legislative institutions and the intellectual opposition parties, lacking real authority in the eyes of the people, will be powerless to stem the popular tide, aroused by themselves, and Russia will be flung into hopeless anarchy.” Which is essentially what happened.

When pressed to mobilize the army, Czar Nicholas for a time temporized, at one point, declaring, “I will not become responsible for a monstrous slaughter.” But on July 30, he surrendered to St. Petersburg’s clamorous war party. Alas, there was no quick victory with allied armies meeting in Berlin. Instead, the losses in manpower and matériel were horrific.

Within a year, St. Petersburg sent some soldiers to the front unarmed, telling them to pick up weapons from fallen comrades. By the end of 1916 Russia had lost some five million men, killed, wounded, captured and missing. The country continued to fight only through the heroism and sacrifice of common soldiers. As another year passed, popular unrest erupted. The Duma’s liberal leader, Pavel Milyukov, asked whether the government’s failures were caused by “stupidity, or treason.”

In March 2017 (February on the old calendar), liberals and moderate socialists staged a revolution, forcing the czar to abdicate. But the Provisional Government’s control was tenuous, and it continued the war amid a series of revolts, mutinies, protests and disturbances—which opened the way for political radicals, most importantly the Bolsheviks, led by Vladimir Ilyich Ulyanov, better known as Lenin.

He began the war in exile in Zurich, Switzerland, but Germany arranged for his passage home to spread the revolutionary virus. He arrived in April and initially had little success. However, the Bolsheviks understood that the people were desperate for peace, land and food.

On November 7, Lenin and his colleagues staged what amounted to a coup against the hapless Provisional Government. The Bolsheviks still were but one faction vying for power. However, Lenin was a political genius: with his leadership they outmaneuvered more moderate forces on the left, made peace with Germany and won a bitter, four-year civil war against the Whites, who were bitterly divided between royalists and liberals but were backed by Imperial Russia’s erstwhile allies.

Lenin then set the repressive foundation of the brutal Soviet state. He was no idealistic dreamer whose good intentions were betrayed by his successors. In 1921, he declared: “We do not promise any freedom or democracy.” His revolutionary colleague Leon Trotsky frankly declared: “We were never concerned with the Kantian-priestly and vegetarian-Quaker prattle about the ‘sacredness of human life.’”

Lenin died in 1924, leading to a bitter succession battle, won by manipulative Joseph Stalin. Under him, millions died, including many of his supporters. Although revolutionary fervor had dissipated, the USSR staggered along, murdering and impoverishing its people, until December 1991. The Soviet flag finally was lowered from the Kremlin for the final time.

Yet the legacy of the Russian Revolution lives on. Scholars figure that communism killed between eight and sixty-one million Soviet citizens; fifteen to twenty million seems most accurate. Stalin mixed murder and famine. His Great Terror made killing routine, with the dictator approving endless lists of victims for execution. His henchmen were desperate to find ever more enemies to satisfy his paranoia: simply inquiring as to the fate of a loved one who’d been detained could result in one’s own arrest and death.

Estimates of the total number of dead due to communism—not counting from wars—run from eighty-five million to upwards of two hundred million. Not only are accurate numbers scarce, but researchers disagree over whether indirect deaths should be included: communist rulers both murdered promiscuously and implemented policies that resulted in mass death—through famine, for instance. The hardship, including poverty, starvation, oppression and inhumanity, is incalculable. Equally brutal was the assault on the human spirit. Marxism as adapted by Leninism squeezed the very life out of people.

Thankfully, as a governing force Marxism is largely dead. A few nominally communist states remain, but most aren’t real or serious. China is essentially fascist. North Korea is a modern version of an ancient Asian monarchy, masked with revolutionary rhetoric. Cuba is edging away from genuine communism. Yet the authoritarian spirit remains alive on the left, even in the West.