The U.S.-Mexican War: 1846-1848, Episode Four "The Fate of Nations"

The U.S. army reaches the Mexican capital defended by 20,000 Mexican soldiers led by lo. The battle for Mexico City begins with heavy casualties on both sides. Mexican defenders fight back courageously, but the capital is finally forced to surrender. General Winfield Scott rides triumphantly into Mexico City to occupy the fabled "Halls of Montezuma." On Feb. 2, 1848, the Treaty of Guadalupe Hidalgo is signed, and a new border is established between Mexico and the United States