The Zimmermann Telegram was a secret diplomatic communication issued from the German Foreign Office in January 1917 that proposed a military contract between the German Empire and Mexico if the United States entered World War I against Germany. With Germany's aid, Mexico would recover Texas, Arizona, and New Mexico. The telegram was intercepted by British intelligence.
The Zimmermann Telegram as it was sent from Washington, DC, to Ambassador Heinrich von Eckardt, the German ambassador to Mexico.
The Mexican Telegraph Company building in Galveston through which the Zimmerman Telegram was relayed
A portion of the Telegram as decrypted by British Naval Intelligence codebreakers. Since the word Arizona was not in the German codebook, it had to be split into phonetic syllables.
The Telegram, completely decrypted and translated
Room 40, also known as 40 O.B., was the cryptanalysis section of the British Admiralty during the First World War.
Room 40 was on the first floor of the main wing of The Admiralty's Old Building, now known as the Ripley Building (built 1726) in Whitehall. It was on the same corridor as the old Board Room.
SMS Magdeburg aground off Odensholm
Zimmermann telegram as decoded by Room 40
