Related Clues:

• A very long time
• Distinctive period of history
• It's a stretch
• Eternity
• Many eras
• Years and years and years and ...
• Near-eternity
• Lo-o-ong time
• Many, many years
• Pliocene, e.g.
• Geologic time division
• Amazingly long time
• An eternity
• Important age
• Longish span