Related Clues:

• "This is only ___" (radio announcement)
• Secret event of '45
• Alamogordo blast
• Mushroom cloud maker, for short
• Los Alamos event
• Explosive event of '54
• Controversial explosion
• Alamogordo trial, briefly
• ''This has been __ . . .''
• Poisonous mushroom producer, briefly?
• Controversial Bikini Atoll event
• 1954 event coded as "Castle Bravo"
• "This is only ___" (part of an old TV message)
• '50s headline event
• Explosion on a range, for short