Thule

Thule, specifically ultima Thule, the furthest Thule:

A fictional location as far north as one can go, where the sun doesn't set in the night time. Kristina Chew calls it Iceland.

The name, Thule, is absolutely ridiculous and perfect for a made-up place.

Nazis thought it was real, but not Iceland, and tried to search for it so it is kind of canceled, unfortunately.