World War I was caused by rising tensions between nations due to alliances, nationalism, imperialism, and militarism. The assassination of Archduke Franz Ferdinand led Austria-Hungary to declare war on Serbia, drawing in allies on both sides. The war quickly escalated into a global conflict as the opposing alliances of the Triple Entente and Central Powers mobilized troops and resources. Trench warfare ensued as the war became a stalemate, with millions of casualties. The United States entry into the war in 1917 on the side of the Allies helped shift momentum, and Germany's defeat in 1918 brought an end to the devastating four-year global conflict.

1. World War I
1914-1918

2. CausesCauses
Alliances
-Triple Alliance (A-H, Germany, Italy)
-Triple Entente (GB, Fr, Russia)
Alliances
-Triple Alliance (A-H, Germany, Italy)
-Triple Entente (GB, Fr, Russia)
Colonial TensionsColonial Tensions
Nationalism and
territorial
tensions (Alsace
and Lorraine).
Nationalism and
territorial
tensions (Alsace
and Lorraine).
Wilhem II
-Economic Rivalry
-Colonial Rivalry
-Military Rivalry
Wilhem II
-Economic Rivalry
-Colonial Rivalry
-Military Rivalry
The Balkans
(Russia and A-H want
to control the area).
The Balkans
(Russia and A-H want
to control the area).
Sarajevo: assassination of
Archduke Franz Ferdinand
Sarajevo: assassination of
Archduke Franz Ferdinand

3. Alliances before WWI

4. Events (before the declaration of war).
• June 1914: Archduke was assassinated by a Bosnian
student in Sarajevo (Bosnia). (Bosnia had been
occupied in 1908 by Austria-Hungary).
• Austria-Hungary accused Serbia.
• Austria-Hungary declared war to Serbia.
• Russia supports Serbia (and all the Slavs of the area)
and moves the troops to the frontier.
• Germany enters into the conflict in order to help its
ally (Austria-Hungary).

5. • Germany asked France to stay neutral (in order to
attack Russia at the east and to avoid two fronts).
France refuses and Germany invades Belgium in its
way to attack France.
• Great Britain enters into the conflict because of the
invasion of Belgium (G.B. and Belgium had signed a
protective alliance).
• Italy will not support Austria-Hungary and Germany.
• The European war has started.
• As this nations have colonies all around the world,
the European conflict is transformed into an
international war.

7. Alliances (during the conflict)
• Triple Entente (or Allies):
– Russia, Great Britain, France
– Italy, Romania, Greece, USA, China and Japan
• Central Powers (previously Triple Alliance):
– Austria-Hungary, Germany
– Ottoman Empire, Bulgaria

8. Development of the Conflict
1. War of movements (1914)
– Schlieffen Plan:
– Russian front
1. Trench Warfare (1914-1917)
2. 1917
3. 1918

9. 1. War of movements (1914)
 The Schlieffen Plan consisted in a rapid an efficient
defeat of France in the Western front (France) and
later to attack Russia moving all the troops through
Germany to the eastern front.
 In the Russian front the Russia army is penetrating
Prussia and Germany is forced to withdraw forces
from the French front.
 The Schlieffen plan has failed

12. 2. Trench Warfare (1914-1917)
• The fronts became stable and due to modern
weaponry is unable to advance without
tremendous casualties.
• The war of movement is transformed into a
war of positions.
• Soldiers started to dig trenches.

13. British soldiers in the trench during the battle of Somme, 1916

14. Trenches

15. 3. 1917
 In 1917 the Russian Revolution took place. They
abandoned the war and the eastern front
disappeared. (The Russians will lose a great part of
their territory).
• In 1917 Germans attacked with submarines in order
to blockade Britain.
• This will cause the entrance of USA (whose ships
were being attacked by the submarines).

16. 3. 1918 (the final phase of the war)
• In 1918 the Germans tried a great offensive to
Paris, but they lost.
• People in Berlin heard the news and they
revolted in the streets against the war.
• Austria-Hungary, Bulgaria and the Ottoman
Empire surrendered.
• Wilhem II was forced to abdicate because of
an uprising. The new republican government
surrendered and signed the armistice.

17. Some important battles
• Battle of Tannenberg (Eastern front): defeat of
Russia by the Germans (180 000 deaths).
• Battle of Verdun (France): German offensive but
without any victory. 700 000 deaths approx.
• Battle of Somme (France): 1 100 000 deaths (60.000
deaths the first day) (nothing of great value had been
gained)
• Battle of Dardanelles (Ottoman Empire): 145.000
killed or wounded.

19. New Weaponry
• New and very destructive weaponry was introduced,
such as: machine guns, flamethrowers, poison gas,
mines, submarines, airplanes, tanks…
• Also the trenches were used for the first time.