When I was younger it was the following clip. Bear in mind that this TV movie was shown during the cold war and promoted as a realistic vision of what
might happen. It also predated CGI and was far more graphic than anything else that had come before.
The Day After was pretty sobering alright...I actually used scenes from it in a persuasive presentation for a college Environmental Science class
quite a few years back, and got pretty powerful reactions to the presentation.