Twice now. Once, about five years ago, exploring more or less by accident, looking for a spellbook another Planeswalker supposedly left there.

[It hadn't been there, in any usable form anyway. The steel it had been etched into been pretty badly corroded, so that made it a bust. But she did meet Nissa there, which was a plus.]

The second time about two years after that. To help a few friends deal with some monsters that had moved in.