Historical clue formulations

• 1950s entertainment innovation ... or a hint to the first and second halves of 17-, 24-, 48- and 60-Across — 2025-11-04
• Small-screen milestone of the 1950s — 2022-08-26
• Invention celebrated by NBC's peacock logo — 2019-06-19
• Invention that prompted NBC to adopt the peacock logo — 2014-09-13
• Development of the 1950's — 2004-08-06
• Technological advance of the 1950's — 2003-10-03