The evolution of the frontlines during World War I in Europe.

On 31 July 1917, the first day of the Third Battle of Ypres (Third Ypres / 31 July 10 November 1917) the British broke through the enemy lines and advanced towards Paschendaele (Passendale). That day the renowned Battle of Pilckem Ridge also took place, with Allied forces beginning a large-scale offensive to push back German lines.
The third battle of Ypres cost approximately 450,000 lives, of which most individuals are still registered as missing in action. On the first day alone 12,000 to 13,000 soldiers died. On that day also the biggest advance was made near Pilckem, giving the site its great symbolic value.