The events of 1917 changed the course of Russian, and indeed world, history. But as these remarkable then-and-now pictures show, pockets of Russia's two largest cities have endured almost unchanged through a century of revolution and the fall, rise, and fall of empire.

The cheering crowds below Nicholas on that summer day had little inkling of it, but their tsar was standing on the edge of an abyss.

Tsar Nicholas II makes a public address on July 20, 1914. A few days later, the tsar would mobilize troops to defend Russia's "little Slavic brothers" in Serbia who were under a barrage of Austrian artillery. This conflict would soon expand into World War I.

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Russia was ill-prepared for war against a coalition led by the highly industrialized Germany. By 1917, the battlefields of WWI had taken around 1 million Russian lives, most of them peasants and workers in soldiers' uniforms who would otherwise have been feeding and supplying Russia's cities. Shortages and hunger became the norm in wartime Russia. In a country where the glittering lives of the nobility had long bred resentment among the lower classes, the war was giving rise to increasingly dark mutterings in the streets and factories. Much of the hostility was directed toward the German-born Tsarina Aleksandra Feodorovna, who many believed was nothing more than a bejeweled German spy.

Russian troops on the Eastern front of WWI .

(Public Domain)

Russia was ill-prepared for war against a coalition led by the highly industrialized Germany. By 1917, the battlefields of WWI had taken around 1 million Russian lives, most of them peasants and workers in soldiers' uniforms who would otherwise have been feeding and supplying Russia's cities. Shortages and hunger became the norm in wartime Russia. In a country where the glittering lives of the nobility had long bred resentment among the lower classes, the war was giving rise to increasingly dark mutterings in the streets and factories. Much of the hostility was directed toward the German-born Tsarina Aleksandra Feodorovna, who many believed was nothing more than a bejeweled German spy.

Russian troops on the Eastern front of WWI . (Public Domain)

With Tsar Nicholas away at the front commanding Russia's war effort, the capital, St. Petersburg (then called Petrograd), was left in Aleksandra's hands. Her "spiritual adviser" was the Siberian mystic Grigory Rasputin, a Russian peasant whose pursuit of prostitutes and raucous drinking sessions had tainted the tsar and tsarina by association.

Aleksandra Feodorovna was by 1917 described by a contemporary as "fiercely and universally hated."

(Public Domain) Grigory Rasputin. In December 1916, the reputedly lascivious holy man was assassinated by Russian noblemen. (Public Domain) Aleksandra Feodorovna (left) was by 1917 described by a contemporary as "fiercely and universally hated." Grigory Rasputin. In December 1916, the reputedly lascivious holy man was assassinated by Russian noblemen. (Public Domain)