What did the letter from Germany sent to Mexico say?

The letter sent from Germany to Mexico in January 1917 is commonly known as the Zimmermann Telegram. It was not a letter but an encrypted telegraph message. The telegram proposed an alliance between Germany and Mexico in the event that the United States entered World War I on the side of the Allies. Germany promised to help Mexico recover territories it had lost to the United States in the Mexican-American War, including the states of Texas, New Mexico, and Arizona. The revelation of the telegram by British intelligence to the United States government was a significant factor in bringing the United States into the war on the side of the Allies.