The fortifications at the Essex Farm cemetery and memorial where in 1915 Canadian physician Lieutenant Colonel John McCrae wrote his famous poem "In Flanders Fields". The work immortalized McCrae and established the poppy as a symbol of remembrance and sacrifice. Located near the Belgium city of Ypres, the British Advanced Dressing Station was first constructed of earthen bunkers cut into a canal bank and later expanded in 1917 and re-enforced with concrete. THE CANADIAN PRESS IMAGES/Mike Dembeck