http://www.slate.com/articles/news_and_politics/history/2015/09/hiroshima_nagasaki_hanoi_how_the_manhattan_project_generation_of_scientists.html

This year marks two somber anniversaries: Seventy years ago, the United States became the first and only country ever to use atomic weapons in war, incinerating the cities of Hiroshima and Nagasaki in the last days of World War II. Two decades later, the massive bombing campaign of Operation Rolling Thunder and the introduction of ground troops in Vietnam ushered in an era of napalm-fueled destruction, Agent Orange defoliation, and brutal “search-and-destroy” missions. The prolonged war cost tens of thousands of American lives and displaced, maimed, and killed millions of Vietnamese.