From Guild Wars Wiki
The Scrying Pool is a large pool of water located in the middle of the Hall of Monuments which shows visions while playing through Eye of the North expansion. The pool can also be used to replay cinematics that a character has already seen or redo major quest missions from the Eye of the North storyline.
[edit] Locations
[edit] Dialogue
- "The water in this pool is so clear its reflection is like a window into another world."
"Look deep into the pool."
- Shows you the nth vision as you progress in the storyline.
"Show me past visions."
- Shows you repeats of visions your character has already seen.
"Show me past events."
- Replays storyline cinematics you character has already seen.
"I seek guidance."
- Allows you to retake repeatable primary quests your character has already completed once.
- When it is time for you to see the next vision, your "effects" monitor will display Call of the Eye when in explorable areas.

Bug.
If you fail to activate a vision before the next one is available, that vision will not show up for that character until you finish the campaign with him. For example, unlocking the third vision before viewing the second one means you can never see the second vision until you complete Eye of the North. Completion of the campaign unlocks all four visions.
[edit] Visions