The Menin Gate Memorial to the Missing is a war memorial in Ypres, Belgium, dedicated to the British and Commonwealth soldiers who were killed in the Ypres Salient of World War I and whose graves are unknown. The memorial is located at the eastern exit of the town and marks the starting point for one of the main roads out of the town that led Allied soldiers to the front line. Designed by Sir Reginald Blomfield and built and maintained by the Commonwealth War Graves Commission, the Menin Gate Memorial was unveiled on 24 July 1927.

In medieval times, the original narrow gateway on the eastern side of the city of Ypres was called the Hangoartpoort, "poort" being the Dutch word for gate. In order to prosper and maintain its wealth, the city of Ypres had to be fortified, to keep out potential invaders. During the 17th and 18th centuries, while under the occupation of the Habsburgs and the French, the city was increasingly fortified. Major works were completed at the end of the 17th century by the French military engineer Sebastien Le Prestre, Seigneur de Vauban. At the outbreak of the First World War in August 1914, the eastern exit simply cut through the remains of the ramparts and crossed a moat. The gateway was by this time known as the Menenpoort, or Menin Gate in English, because the road leading through the gateway led to the small town of Menen.

More Info: en.wikipedia.org