In the period from 1905 to 1917 the population of St. Petersburg rose by 58%, largely as a result of migration. Qualitative changes also took place. The growth by 3% of the proportion of women is evidence of an increase in the permanent population, as seasonal workers who moved to the city with their families became city residents. The proportion of workers and independent professions rose, while the proportion of nobles fell. In total, the "non-privileged" classes accounted for more than 85% of the capital's population. The city remained multiethnic and multicultural. It had newspapers and magazines in German, Polish, Finnish, Yiddish and other languages, and French and German theatrical companies.
By now newcomers constituted one third of the capital population and housing, especially inexpensive housing, was scarce. The population of outlying districts grew rapidly, but only two attempts were made to create quarters with modern amenities in the new districts, the Harbor township on Vassilyevsky Island and the Nobel plant workers township. As a first priority apartment buildings with rental units, hotels, and trade centers were built. During these years Vasilyev, Krichinsky, Fomin, Shchuko and many other noted architects already well known during the preceding period, worked actively. In 1907 the Yeliseyev's trade center containing a theater was built on Nevsky Prospect (arch. Baranovsky); in 1910, the hotel Astoria was erected on St. Isaac's Square (arch. Lidval'); in 1913 the Great Mosque was built in the Petrograd district (archs. Vasilyev, Krichinsky and Von Gogen).
The unsystematic development of the outskirts caused the most farseeing architects to consider planning new districts. Fomin jointly with Lidval prepared the "New St. Petersburg" general project for development of Goloday Island, but the implementation of this plan was interrupted by war and revolution. At the same time, architects and experts in fine arts began to raise the question of study and preservation of the architectural heritage. A distinguished historian and theoretician of Russian art, Igor Grabar, began to systematize this work. In 1908 the Society for the Protecting and Preservation of Monuments of Arts was founded in Petersburg and soon thereafter the Museum of Old St. Petersburg was opened.
The first fifteen years of the 20th century saw a rapid growth of industry, especially metal-working, in the capital. In addition to state-owned plants fulfilling defense orders, 10 private plants were engaged in metalwork and engine production, the largest of them being the Nobel and Aivaz plants. A majority of Russia's electrical engineering and shipbuilding plants were also located in the city. The first Russian steamships were built at the St. Petersburg shipyards. With its seaport and railroad lines, the city served as one of the country's main junctions. As the expansion of the city generated the need for new roads and new means of transport, another 2 bridges across the Neva - the Palace and Peter the Great bridges - were built and regular tram and bus service provided.
Between 1905 and 1907 St. Petersburg was the stage of violent political activities. The army's shooting at the workers' demonstration on January 9, 1905 sparked the First Russian revolution. In the fall of 1905 the St. Petersburg Soviet of Workers' Deputies controlled most enterprises, threatening the whole system of administration. The revolutionary movement in the capital began to decline after the Soviet members, headed by Trotsky, were arrested in December 1905. A short peaceful period after the defeat of the revolution ended in 1910 with new strikes and demonstrations shaking the city. In the summer of 1914, shortly before the war, there were barricades and fighting in the working-class districts, but once the war broke out patriotic sentiments prevailed, manifesting themselves in demonstrations in support of the government.
After the beginning of the First World War, St. Petersburg was renamed Petrograd, but the name was not the only thing that changed. With enlistment offices and soldiers in the streets, the city itself looked different. Soon, refugees began to arrive. Evacuation of enterprises from the western provinces contributed to the growth of the city's industry, where many women were employed to replace the mobilized men. Some petty traders and petty bourgeois became workers at military plants in order to avoid mobilization (these people were called "uchetchiki"). The rise in prices outpaced the rise in wages. The increase in the population, together with disorganization of railroad transport, led to food shortages, with the first food lines appearing in 1916. High social tension caused a number of strikes and later took the form of open confrontation.