- 1917 31 Jul Third Battle of Ypres (Passchaendale), a British-led attempt to break the German line in Flanders, begins.
- 1919 31 Jul The Weimar Republic, Germany's first liberal, democratically-elected government, is established.
- 1998 31 Jul The UK government imposes a total ban on the use of landmines by British armed forces.

