Answer:
Russo-Japanese War (1904-1905): Triggered by territorial tensions between Russia and Japan in the Far East. Russia saw its fleet destroyed during the Battle of Tsushima in 1905. The Russian people concluded that the Tsarist regime was unable to manage military affairs and sparked demonstrations and social unrest that led to the issuance of the October Manifesto by Tsar Nicholas II in 1905. This manifesto promised reforms policies, including the creation of the State Duma (a legislative body), in an effort to quell social unrest.
The 1905 Revolution: The October Manifesto promised reform, but unsatisfactory for many Russians. Economic, social and political problems persisted, fueling general discontent. Revolutionary movements and popular uprisings continued to develop, highlighting the desire for change and democracy and leading to the questioning of Tsarist authority
World War I (1914-1917): Massive casualties, economic hardship and government mismanagement of the war aggravated the country's internal problems: food shortages and civil unrest. The latter ultimately leading to the abdication of Tsar Nicholas II. This marked the end of the Romanov dynasty and paved the way for the February Revolution which overthrew the Tsarist regime and established a Provisional Government.