Dos Equis ("Two X's") is a Mexican beer made by the Cuauhtémoc Moctezuma Brewery. It was originally called "Twentieth Century" (Siglo XX).
There are several types of Dos Equis beer. The original is an amber lager packaged in brown bottles. Then came a Special Pale lager in green bottles. In 2014 came "Azul". It has a more robust taste, made from blue agave nectar and some new spices.
Dos Equis is well known in Mexico and the United States. This is partly because of advertisements called "The Most Interesting Man in the World". These ads have actor Jonathan Goldsmith and a narrator telling of his amazing exploits.