World Leaders commemorate start of WWI

French President François Hollande joined world leaders on Monday to commemorate the centenary of the outbreak of World War 1 in the industrial town of Liège in eastern Belgium.

The King and Queen of Belgium greet the Duke and Duchess of Cambridge for the commemoration of WW1 on August 4, 2014. REUTERS/Laurent Dubrule

Speaking at the service, Hollande said Belgium had been the first battleground of the Great War and that the country offered "solid resistance".

Hollande also used the occassion to bring the day's current calamities to the forefront and called for action to end to massacres in Gaza where over 1,800 - many of them civilians - have died in Israeli attacks against Hamas.

"When I see what is happening with the Christians in Iraq, the minorities in Syria, massacres every day. What is happening too in Gaza, massacres...We have to act," Hollande said.

Liège was under tight security on Monday to ensure the safety of heads of states in attendance, including King Philip VI of Spain, German president Joachim Gauck, and members of the British and Belgian royal families.

Presidents of Austria, Armenia, Ireland, Serbia, Montenegro, Romania, Bulgaria and Albania were also present.

A total of 83 heads of states whose countries were involved in World War 1 were invited.

The ceremony began at the Abbaye Saint-Laurent with an opening speech by Belgium's King Philippe, and will move to the Allied War Memorial of Cointe for a wreath laying and a minute's silence.

While the Great War originated in the Balkans in July 1914, it spread globally one month later after Germany invaded a neutral Belgium and raged on for four years.

A heavily fortified Liège put up a strong fight against the German forces at the start of the war in 1914 but eventually fell to the Germans on August 15.

The city, which was later awarded the prestigious Legion d’Honneur by France for its heroic defence, was flattened and thousands of people died in the siege.

Germany’s defiance of Belgium’s neutrality triggered World War 1, which in four bloody years saw the death of some 17 million soldiers and civilians, 20 million injured and the world forever changed.