New Mexican oil legislation goes into effect, leading to the formal outbreak of the Cristero War.

Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundaries with the Pacific Ocean to the west, the Caribbean Sea to the southeast, and the Gulf of Mexico to the east. Mexico covers 1,972,550 km², and is the thirteenth-largest country in the world by land area. With a population exceeding 130 million, Mexico is the tenth-most populous country in the world and is home to the largest number of native Spanish speakers. Mexico City is the capital and largest city, which ranks among the most populous metropolitan areas in the world.

The Cristero War, also known as the Cristero Rebellion or La cristiada, was a widespread struggle in central and western Mexico from 3 August 1926 to 21 June 1929 in response to the implementation of secularist and anticlerical articles of the 1917 Constitution. The rebellion was instigated as a response to an executive decree by Mexican President Plutarco Elías Calles to strictly enforce Article 130 of the Constitution, an implementing act known as the Calles Law. Calles sought to limit the power of the Catholic Church in Mexico, its affiliated organizations and to suppress popular religiosity.

January 1 is the first day of the calendar year in the Gregorian Calendar; 364 days remain until the end of the year. This day is also known as New Year's Day since the day marks the beginning of the year.