Codes in world War I

You may well have heard of the code breakers in World War II and the German Enigma machine, but did you know that Britain had a team of cryptanalysts in World War I who intercepted a coded telegram from the Germans in 1917? This telegram, which was sent to the German minister in Mexico, stated that Germany was going to lauch a submarine attack on the USA and if Mexico joined them it would be rewarded with three of the American states. This was one of the key events which led to the USA joining the war on the side of the Allies.