Plaque

The Menin Gate commemorates 54,395 British and Commonwealth soldiers who died in the Ypres Salient between 1914 and 1918, and have no known grave. Designed by Sir Reginald Blomfield and unveiled on July 24, 1927, it was built by the Imperial War Graves Commission, now the Commonwealth War Graves Commission. The memorial is constructed in a classical style, with a large central arch flanked by smaller arches, and is lined inside and out with panels inscribed with the names of the missing. It stands on the route once used by soldiers heading to the front lines. Originally flanked by stone lions, the gate lost them during World War I; replicas were later installed, and the original lions were sent to Australia, where they are now preserved.

While the Menin Gate does not directly commemorate U.S. servicemen who served in the American Expeditionary Forces (AEF), it does include American-born soldiers who served with British or Commonwealth units and died in the Ypres Salient during WWI without a known grave. Some U.S. citizens voluntarily enlisted in Canadian, British, Australian, or other Commonwealth forces before the U.S. entered WWI in April 1917. These Americans, once part of Commonwealth units, are recorded and commemorated by the CWGC — and if missing in the Ypres Salient, they may be named on the Menin Gate. Example: An American-born soldier serving in the Canadian Expeditionary Force (CEF) and killed in the Ypres region with no known grave would be listed here.

Source of information: en.wikipedia.org