What 10 cities in Europe were involved ww1?

The 10 cities that were involved in WWI in Europe are:

1. Sarajevo, Bosnia and Herzegovina (Assassination of Archduke Franz Ferdinand)

2. Belgrade, Serbia (Austrian-Serbian conflict escalation)

3. Berlin, Germany (German Declaration of War on France and Russia)

4. Paris, France (Capital of France, site of the Western Front)

5. London, United Kingdom (Capital of the United Kingdom, involved in the Western Front)

6. Vienna, Austria (Capital of Austria-Hungary, center of the Austro-Hungarian Empire)

7. Warsaw, Poland (Strategic city in Eastern Europe, fought over by the Central Powers and Russian Empire)

8. Ypres, Belgium (Site of major battles on the Western Front)

9. Verdun, France (Site of a major battle on the Western Front)

10. Saint Petersburg, Russia (Capital of the Russian Empire, site of the Russian Revolution in 1917)