The Museum exhibit highlights how one decoded message changed the course of history during World War I. The Germans planned to cut off supply lines to Britain and France by beginning unrestricted submarine warfare in the Atlantic. Fearing the United States would join the battle if their ships were sunk, Germany asked Mexico to start a war with the United States and promised the return of Texas, Arizona, and New Mexico. The request was sent from the foreign minister in Berlin, Arthur Zimmermann, through the German ambassador in Washington, D.C., to the German ambassador in Mexico City, in the form of a coded message. It became known as "The Zimmermann Telegram." Britain intercepted the message as it was transmitted overseas. Royal Navy cryptanalysts decoded and showed the message to the United States. Ultimately, Congress declared war on Germany. Thus, a single coded message, and the efforts of cryptanalysts, changed history.