In late June 1914, Archduke Franz Ferdinand of Austria was assassinated by a Serbian nationalist in Sarajevo, Bosnia. An escalation of threats and mobilization orders followed the incident, leading by mid-August to the outbreak of World War I, which pitted Germany, Austria-Hungary and the Ottoman Empire (the so-called Central Powers) against Great Britain, France, Russia, Italy and Japan (the Allied Powers). The Allies were joined after 1917 by the United States.
War I ended in the defeat of the Central Powers in November 1918, more than 9 million soldiers had been killed and 21 million more wounded.
Source: World War I History - World War I - HISTORY.com

Europe:

Source: California State Univ. Northridge


Middle East:

During WWI the combatants in the Middle East were on the one hand, the Ottoman Empire (including Kurds, Persians and some Arab tribes), with some assistance from the other Central Powers consisting of Germany, Austria-Hungary, the Ottoman Empire and Bulgaria, and on the other hand, the British (with the help of Jews, Greeks, Assyrians and the majority of the Arabs), the Russians (with the help of Armenians) and the French from the Allies of World War I.
Source: Middle Eastern theatre of World War I - Wikipedia

The Ottomans ran a multilingual, multireligious empire, ruled by a sultan who also bore the title of caliph--commander of all the world's Muslims. Having joined the losing side in the Great War, however, the Ottomans saw their empire summarily dismantled by European statesmen who knew little about the region's people, geography and customs.
  The secret Sykes Picot agreement of 1916 divvied up the Middle East between Britain and France.
  Britain and France- carved up the region into spheres of influence in blatant contradiction of solemn promises to grant the natives independence. Instead of sovereignty, the Arab people were subjected to a protectorate status or League of Nations mandates.
Some say they deliberately drew maps to put fighting ethnic groups together, so they could establish power to keep the peace.

Moreover, the post-war re-mapping bestowed legitimacy on a colonial settler movement, depriving the indigenous Palestinians of their right to their land and their ancestral home.
  The resulting Middle Eastern states were often artificial creations.
Source: Remapping the Middle East | CounterPunch.org
  The built-in imbalances in some of these newly carved-out states--particularly Syria and Iraq--spawned brutal dictatorships that succeeded for decades in suppressing restive majorities and perpetuating the rule of minority groups.
  The rise of Islamic State (ISIS) is the direct result of this meltdown. The Sunni extremist group's leader, Abu Bakr al-Baghdadi, has proclaimed himself the new caliph and vowed to erase the shame of the "Sykes-Picot conspiracy."
Source: Would New Borders Mean Less Conflict in the Middle East? - WSJ
See also:
Imagining a Remapped Middle East - NYTimes.com.
Century of Violence: Imperialistic Dealings - SPIEGEL ONLINE


On November 2, 1917, Britain issued the Balfour Declaration:
His Majesty's Government views with favor the establishment in Palestine of a national home for the Jewish people, and will use their best endeavors to facilitate the achievement of this object, it being clearly understood that nothing shall be done which may prejudice the civil and religious rights of existing non-Jewish communities in Palestine or the rights and political status enjoyed by Jews in any other country.

Links:
Middle East during World War I

last updated 8 Nov 2014