What diplomatic communication did Germany send to Mexico, urging them to attack the U.S.?

The Zimmerman Telegram is a significant historical document because it was a secret diplomatic communication sent by Germany to Mexico during World War I in January 1917. In this telegram, Germany proposed a military alliance with Mexico in the event that the United States entered the war against Germany. The message encouraged Mexico to attack the U.S., promising support for the recovery of territories such as Texas, New Mexico, and Arizona, which had been lost in the Mexican-American War.

The importance of the Zimmerman Telegram lies in its role in shifting public opinion in the United States against Germany, as its interception and subsequent publication heightened fears about German ambitions and contributed to the U.S. entering the war. The urgency of the communication, its clandestine nature, and the promises it made to Mexico make it a pivotal moment in diplomatic history during World War I.