Mexican coat of arms

The coat of arms of Mexico (Spanish: Escudo Nacional de México, lit. "national shield of Mexico") is a national symbol of Mexico and depicts a Mexican (golden) eagle perched on a prickly pear cactus devouring a rattlesnake. The design is rooted in the legend that the Aztec people would know where to build their city once they saw an eagle eating a snake on top of a lake. The image has been an important symbol of Mexican politics and culture for centuries. To the people of Tenochtitlan, this symbol had strong religious connotations, and to the Europeans, it came to symbolize the triumph of good over evil (with the snake sometimes representative of the serpent in the Garden of Eden).

The Mexican law on the National Arms, Flag, and Anthem regulates the name, the design, and the use of the arms. There they are officially called "coat of arms" (Spanish: escudo, literally "shield"), even if there is no heraldic shield and therefore, according to the rules of heraldry, it is not a traditional "coat of arms" and more precisely a "national emblem" instead (National Emblem of Mexico). It is in the center of the flag of Mexico, is engraved on the obverse of Mexican peso coins, and is the basis of the Seal of the United Mexican States, the seal used on any official documents issued by the federal, state or municipal governmental authorities. The seal differs from the arms by the addition of the words Estados Unidos Mexicanos ("United Mexican States", the full official name of the country) in a semicircle around the upper half.