great Faerie sites?

What would you nominate as some of the great Faerie sites of Mythic Europe?

For example, say a Merinita maga wanted to make a pilgrimage to three places of undisputed Faerie influence, as part of her advancement within the House. What are some ideas for where, and what, these places would be? I'd be happy to hear your suggestions based on ArM canon, on historical legend, or on inventions from your own sagas.

Irencilla and Stonehenge immediately spring to mind. The DOmus magna and the largest stone circle ever built (I think). If a dolmen has some Good Folk residents, imagine Stonehenge!!

Cheers,
Xavi

Two very good suggestions, for sure.
What else?!

A bit iffy, but if you take the Titanomachi as a battle between Olympean Faeries and Magical Titans then the regio at the gate of Gibraltar, where Atlas holds the sky above the earth, is a potent Faerie regio where one of the strongest Titans is bound.

Other places of bound titans include Arkona (where the North Sea spirit is bounds are renewed yearly), and presumably certain areas of Tartarus where the other Titans are bound (accessible through Coeris).

I would also count one place of Arthurian myth, perhaps Glastonbury. Perhaps Merlin's grave, or Morganna's court, or so on.

A rather obvious one: Mount Olympus.

All of the above are very good ideas.
A couple other suggestions:
The Island of Avalon.
The Minotaur's Labyrinth on Crete.
The Black Forest in Germany (very well-detailed in the Rhine book).
A dwarven swordsmith shop in Toledo.

The RosenGarten (Garden of Roses) in the Dolomites (Alps). There's a legend explaining why these mountains appear rose-colored at dawn and dusk. In a nutshell, they were the domain of this dwarf king, and they were covered with roses, but the dwarf king put an enchantment on them so that they would not be visible during the day or during the night. But dawn and dusk are neither day nor night, so the enchantment fails at these times, and the roses are revealed.