Related Clues:
- Huge spans
- What mountains rise over
- So long I can't conceive of it, let alone write a good clue for it!
- Mountains formed over them
- Many millenia
- Gazillion years
- Long periods of leisure on sabbatical
- Long span
- Myriad eras
- Bunch of eras
- Numerous centuries
- Apparent stretch between Christmases, to kids
- Cosmic periods
- Stars exist over them
- Quite a long while