Un-removable forts?

[Susanna]

I haven't tried this myself, but my intuition would be that you might need a unit in the fort to dismantle it.

Unfortunatly no. Even with a unit inside, the "destroy building" button remains grey. Stationing a genereal doesn't help either.

Unless there is some super-special-trick that I haven't found yet it does indeed look like forts are permanent

Susanna/Calapine