If I remember correctly, "Agent Orange" is originally designed in ww2 for dropping in Japan if they don’t surrender. But Japan surrendered after Abomb so they used in Vietnam.
2:56 I have been here, I did my IELTS in ho chi Minh city, after the oral exam I got one day left for spending all my Vietnamese dong(otherwise I have to exchange them to US dollar first then exchange to Chinese Yuan → 多くの料金を無駄にする)