Ottoman Empire:

The defeat and dissolution of the Ottoman Empire (19081922) began with the Second Constitutional Era, a moment of hope and promise established with the Young Turk Revolution. It restored the Ottoman constitution of 1876 and brought in multi-party politics with a two-stage electoral system (electoral law) under the Ottoman parliament. The constitution offered hope by freeing the empire's citizens to modernize the state's institutions, rejuvenate its strength, and enable it to hold its own against outside powers. Its guarantee of liberties promised to dissolve inter-communal tensions and transform the empire into a more harmonious place. Instead, this period became the story of the twilight struggle of the Empire. Young Turks movement members once underground (named committee, group, etc.) established (declared) their parties. Among them "Committee of Union and Progress," and "Freedom and Accord Party" were major parties. On the other end of the spectrum were ethnic parties which included; Poale Zion, Al-Fatat, and Armenian national movement organized under Armenian Revolutionary Federation. Profiting from the civil strife, Austria-Hungary officially annexed Bosnia and Herzegovina in 1908. The last of Ottoman censuses was performed with the 1914 census. Ottoman military reforms resulted with the Ottoman Modern Army which engaged with Italo-Turkish War (1911), Balkan Wars (19121913), and continuous unrest (Counter coup followed by restoration and Saviors followed by Raid on Porte) in the Empire up to World War I.

Please answer a question about this article. If the question is unanswerable, say "unanswerable". What was the revolution that sparked the end of the Ottoman Empire?
the Young Turk Revolution