(CBS News) For the people of Mexico, the "Halls of Montezuma" are much more than the words of a song; they represent a humiliating military defeat at the hands of the United States in 1847. Not even the 1862 victory over France that Mexico celebrates today -- Cinco de Mayo -- is enough to fully heal the wound. Mo Rocca tells the story:
Every year, in a small cemetery in Mexico City, 750 unknown American soldiers who died in the Mexican-American War are remembered.
"That conflict marked a dark chapter in the long relations between our countries," said U.S. Ambassador Earl Anthony Wayne. He has to tread diplomatically over an issue that's still raw south of the border.
"Here in Mexico, of course, they remember it because large parts of the United States were parts of Mexico before that war," said Wayne.
But north of the border, the war is all but forgotten.
In 2008 an Absolut Vodka ad showing a map of Mexico stirred outrage in America: Was Absolut calling for Mexico to conquer the U.S.?
In fact, this is what North America looked like c. 1847:
Penn State historian Amy Greenberg says it was the first war in U.S. history that was fought for greed rather than principle: "There was no great ideological reason why we were going to war against Mexico. It was the first war that was started with a presidential lie."
Greenberg argues in her recent book, "A Wicked War," that the war was engineered by President James Polk.
"James K. Polk went to Congress and said American blood had been shed on American soil, but almost nobody except Americans claimed that the land where the blood was shed was actually American soil," Greenberg said. "When Zachary Taylor marched his troops between the Nueces and the Rio Grande, he was marching through land which everybody, including the residents of that territory, believed to be Mexican land."
"So they were basically looking for a fight?" asked Rocca.
"Absolutely. No question about it."
They were looking for a fight because President Polk had a vision for America called "Manifest Destiny."