Stamnagathi
(Cretan Green)

It is one of the 'wild' greens (I don't believe nowadays all of these wild greens are actually wild) that Greeks boil and eat with salt, olive oil and vinegar/lemon juice.
Stamnagathi (Spiny chicory) is usually associated with Crete, but can be grown and eaten also elsewhere. If you want to eat it in a restaurant, the best shot will be in a Cretan one.

It is relatively expensive as a wild green: it is typically 3 to 7 times more expensive than cheaper greens.
It is only slightly bitter and crunchy texture is particularly pleasant.

When we ordered Stamnagathi in Crete, to our surprise, it was offered as salad.