English: Four primary types of nuclear testing: 1. atmospheric, 2. underground, 3. upper-atmosphere, 4. underwater.

The illustration is meant to just be schematic about the locations and general characteristics of these types (atmospheric tests created mushroom clouds and fallout; underground tests create seismic activity; upper-atmospheric tests have all sorts of weird ionization and EMP effects but are too high to have much fallout; underwater tests create mushroom clouds with lots of water vapor).

The specific setups of the illustration (a tower shot, an underground instrumentation tower, a rocket, mooring to a ship) are arbitrary but not uncommon in the history of nuclear testing.