"The 20th of November is celebrated in Mexico as the beginning of the Mexican Revolution that ran from 1910 to 1920 and was called for by defeated presidential candidate and reform writer Francisco Ignacio Madero."
"The Plan of San Luis Potosí
While in exile in San Antonio, Texas Madero wrote a political document that was later published in the Mexican city of San Luis Potosí and hence became known as "The Plan of San Luis Potosí." Madero called for the people of Mexico to rise up and begin a revolution some 45 days later at 6PM on November 20th.
On November 20, 1910, Madero arrived at the border and planned to meet up with 400 men raised by his uncle Catarino to launch an attack on Ciudad Porfirio Díaz, modern-day Piedras Negras, Coahuila. However, his uncle showed up late and brought only ten men. Discretion being the better part of valor, he postponed the armed conflict to begin the revolution."Edited: 10:49 am, November 20, 2012