Every evening at 8pm the last post is played by members of the Ypres Firebrigade under the arches at the Menin Gate, Ypres, Belgium. Visitors attend and can lay wreaths in memory of those 54,406 Officers and Men lost to the Flanders mud in WW1 and have no known grave. Their 54,406 names are inscribed on the Commonwealth War Graves Commission memorial at one of the exit road from where the troops in WW1 went to the front line.

Caption information below is from the CWGC web site:

The Menin Gate is one of four memorials to the missing in Belgian Flanders which cover the area known as the Ypres Salient. Broadly speaking, the Salient stretched from Langemarck in the north to the northern edge in Ploegsteert Wood in the south, but it varied in area and shape throughout the war.

The Salient was formed during the First Battle of Ypres in October and November 1914, when a small British Expeditionary Force succeeded in securing the town before the onset of winter, pushing the German forces back to the Passchendaele Ridge. The Second Battle of Ypres began in April 1915 when the Germans released poison gas into the Allied lines north of Ypres. This was the first time gas had been used by either side and the violence of the attack forced an Allied withdrawal and a shortening of the line of defence.

There was little more significant activity on this front until 1917, when in the Third Battle of Ypres an offensive was mounted by Commonwealth forces to divert German attention from a weakened French front further south. The initial attempt in June to dislodge the Germans from the Messines Ridge was a complete success, but the main assault north-eastward, which began at the end of July, quickly became a dogged struggle against determined opposition and the rapidly deteriorating weather.