Revolution and the revolutionary era. When it opened in 1969 with line 1 (the "Pink Line"), two stations alluded to the Revolution. Most directly referencing the Revolution was Pino Suárez, named after Francisco I. Madero's vice president, who was murdered with him in February 1913. The other was Balderas, whose icon is a cannon, alluding to the Ciudadela armory where the coup against Madero was launched. In 1970, Revolución opened, with the station at the Monument to the Revolution. As the Metro expanded, further stations with names from the revolutionary era opened. In 1980, two popular heroes of the Revolution were honored, with Zapata explicitly commemorating the peasant revolutionary from Morelos. A sideways commemoration was División del Norte, named after the Army that Pancho Villa commanded until its demise in the Battle of Celaya in 1915. The year 1987 saw the opening of the Lázaro Cárdenas station. In 1988, Aquiles Sedán honors the first martyr of the Revolution. In 1994, Constitución de 1917 opened, as did Garibaldi, named after the grandson of Italian fighter for independence, Giuseppe Garibaldi. The grandson had been a participant in the Mexican Revolution. In 1999, the radical anarchist Ricardo Flores Magón was honored with the station of the same name. Also opening in 1999 was Romero Rubio, named after the leader of Porfirio Díaz's Científicos, whose daughter, Carmen Romero Rubio, became Díaz's second wife. In 2012, a new Metro line opened with an Hospital 20 de Noviembre stop, a hospital named after the date that Francisco I. Madero in his 1910 Plan de San Luis Potosí called for rebellion against Díaz. There are no Metro stops named for Madero, Carranza, Obregón, or Calles, and only an oblique reference to Villa in Metro División del Norte. Each station is identified by a minimalist logo, first designed by Lance Wyman, who had also designed the logo for the 1968 Mexico Olympics. Logos are generally related to the name of the station or the area around it. At the time of Line 1's opening, Mexico's illiteracy rate was high. As of 1960, 38% of Mexicans over the age of five were illiterate and only 5.6% of Mexicans had completed elementary school. Since one-third of the Mexican population could not read or write and most of the rest had not completed high school, it was thought that patrons would find it easier to guide themselves with a system based