Another great gallery from Boston.com's The Big Picture, showing a retrospective of iconic images from the Vietnam War.

Well-known images include:

- General Nguyễn Ngọc Loan executing a Viet Cong prisoner in Saigon by Eddie Adams (but with before and after images).
- the self-immolation by Buddhist nun in protest of the South Vietnamese regime
- the aftermath of the Kent State massacre
- fleeing villagers after a napalm strike including the terrified, naked Kim Phuc
- and released pilot Robert Sim being greeted on the tarmac by his family.

More on the execution of the Viet Cong prisoner

I'm a bit surprised that the Big Picture didn't 'cover' the photo of the execution of the Viet Cong prisoner as they did for other disturbing images. Could it be that the image is so well-known that they assume most people have already seen it? It is probably one of the most famous photos in photojournalism, certainly, and won Adams the Pulitzer Prize. A shocking moment that never fails to give me the chills when I see it.

You may be interested in learning the background behind the events leading up to the execution, especially in Adams' opinion of his own image. He decried the impact of the image and personally considered General Loan a hero.