Related Clues:

• Geological time period (Var.)
• 1 billion years
• A billion years (Var.)
• 365 billion days, astronomically
• Interminable stretch
• '-- Flux' (1995 TV series)
• Almost eternity
• Longish span of time
• Millennia on end
• Eternity, at Eton
• Geological span
• '-- Flux'
• ''___ Flux''
• Billion years (Var.)
• History unit