The Atomic Cloud.

Two journalists drop by the Waterloo studios, where a director shows them a rough cut of a pacifist film. In it, a botched atomic test in Belgium creates a clay cloud that spreads world peace, causing stock markets to crash and weapons manufacturers to lose their jobs.The journalists roast the movie for being unrealistic, but the director defends it as a wake-up call to maintain peace. Afterward, they tour the studios, giving a cool look behind the scenes.