on the day August 1, 1914, four days after Austria-Hungary declared war on Serbia, two more great European powers—Russia and Germany—declare war on each other; the same day, France orders a general mobilization. The so-called “Great War” that ensued would be one of unprecedented destruction and loss of life, resulting in the deaths of some 20 million soldiers and civilians and the physical devastation of much of the European continent. hope this helps :)
