Men on board a ship put on protective goggles to watch an hydrogen bomb test; a huge mushroom cloud forms.

The video describes a massive explosion that vaporizes an island, creating a giant fireball and a mushroom cloud filled with radioactive dust. This cloud rises 25 miles into the sky. Another bomb test results in radioactive fallout affecting Japan.

To what height does the mushroom cloud rise?

What effect does another bomb test have on the Japanese?