|"Is this all real? Or has this been happening inside my head?"
The subject of this article is a real-life person, company, product, or creative work that has been mentioned "in-universe" in a canon source. The Harry Potter Wiki is written from the perspective that all information presented in canon is true (e.g., Hogwarts really exists), and, as such, details contained in this article may differ from real world facts.
The North Sea is a body of water in northwestern Europe, separating the island of Great Britain from the continental mainland. The Dover Strait and the English Channel in the south, and the Norwegian Sea in the north, connect it to the Atlantic Ocean.