Mexican–American War: Six teenage military cadets known as Niños Héroes die defending Chapultepec Castle in the Battle of Chapultepec. American troops under General Winfield Scott capture Mexico City in the Mexican–American War.

The Mexican–American War, also known in the United States as the Mexican War and in Mexico as the United States intervention in Mexico, was an invasion of Mexico by the United States. It followed the 1845 American annexation of Texas, which Mexico still considered its territory because it refused…