Related Clues:

• 100 years: Abbr
• Time line period: Abbr
• 100-yr. stretch
• Fivescore yrs
• 21st, e.g.: Abbr
• Noted arcade classic, and this puzzle's theme
• 800s, e.g.: Abbr
• Historic span: Abbr
• One hundred yrs. (Abbr.)
• The 2000s, e.g.: Abbr
• Long life: Abbr
• It’s usu. 36,524 days