Heads of state and foreign dignitaries, including German President Joachim Gauck and his French counterpart Francois Hollande, are gathering at an Allied memorial to commemorate the start of World War I.
In a spirit of reconciliation among former enemies, Belgian King Philippe and Queen Mathilde welcomed Gauck under cloudy skies for the late-morning ceremony amid pomp and military honour.
Germany invaded neutral Belgium on August 4, 1914, as part of a planned attack on France.
By nightfall, Britain had joined the war.
The war was not expected to last long.
Instead, over four years, the continent was plunged into unknown hardship and misery.
Further remembrance events are planned in Belgium and Britain throughout the day. - Sapa-AP