Germans sweep through Belgium

As the war cards were played in a deadly poker game among nations in the west of Europe, hostilities broke out in the east. The Austro-Hungarian empire, prodded secretly by Germany, declared war on Serbia on July 28, in reprisal for the assassination of Archduke Franz Ferdinand and Duchess Sophie.

An insignificant dissident shot the Archduke and his wife a month earlier. Initially, relations between the two nations were not strained but the incident was used by Vienna to escalate tensions, break diplomatic ties and declare war. As Russia mobilised to support its ally Serbia, Germany declared war on Russia on August 1. Mobilisation was ordered in France to support its ally Russia; on August 3 France and Germany declared war on each other.

Germany’s invasion of neutral Belgium to attack France prompted Britain to declare war on Germany. The summer of 1914 was shattered as millions marched into the industrial era’s first world war – four years of the greatest carnage humankind had ever known.
https://www.history.com/this-day-in-history/austria-hungary-declares-war-on-serbia

An American journalist sat in a Brussels café and watched the German army’s march through the Belgium capital. ‘There was a machine, endless, tireless, with the delicate organisation of a watch and the brute power of a steam roller. And for three days and three nights through Brussels, it roared and rumbled.’ Richard Harding David, an American newspaper reporter.
http://www.eyewitnesstohistory.com/brussels.htm

‘It is my Royal and Imperial Command that you exterminate the treacherous English and march over General French’s contemptible little army. You will be home before the leaves have fallen from the trees.’ Kaiser Willhelm II speaking to German troops in August 1014.

August 1914: France’s worst day
In the Battle of the Frontiers on August 22, 1914, more French soldiers died than in any other day in history as they fought valiantly against the invading Germans. As vast armies were mobilised at the same time, 27,000 French soldiers died in less than 24 hours.
The German advance was slowed but painful lessons were learned as fiercely courageous French officers willingly sacrificed their lives and those of their men instead of withdrawing strategically.
http://www.france24.com/en/20140822-august-22-1914-battle-frontiers-bloodiest-day-french-military-history