Possible Clues:

• Vast period of time
• Long period of time
• A one-off time period
• "___ Flux" (2005 Charlize Theron movie)
• It feels like forever
• '___ Flux' (Charlize Theron film)
• A long time
• Immeasurably long period of time
• At least two eras
• "___ Flux" (Theron movie)