Ceremony in Belgian city of Liege marks anniversary of outbreak of World War invaded neutral Belgium on the next four years , and Liege declared war . Over August 4 , 1914 , 16 million people died in the conflict , many on Belgian battlefields . Duke said war was now `` unthinkable '' between nations who had fought .
Ceremony in Belgian city of Liege marks anniversary of outbreak of World War I. Germany invaded neutral Belgium on August 4 , 1914 , and Britain declared war . Over the next four years , 16 million people died in the conflict , many on Belgian battlefields . Prince William said war was now `` unthinkable '' between nations who had fought .