The "Halls of Montezuma" marked a decisive triumph of U.S. forces in the Mexican-American War
For the U.S., the Mexican-American War expanded its territory as a victory of manifest destiny; for Mexicans, the "American Invasion" still stirs emotions 165 years later. Mo Rocca traveled to Mexico City and the site of the Battle of Chapultepec to learn about a "forgotten war" that helped determine the fate of North America.