I've often wondered, as an American with little to no knowledge of naming conventions outside this country, why is it called the Isle of Man? it is very fantasy movie-esque to me.
"Behold! The Isle of Man! Nonhumans dare not approach!"
The etymology isn't certain, but there are a few potential explanations. The island is also called Mann, which translates to Mannin in Manx Gaelic (the newest hotel on the island is the Mannin), and our head of state is the Lord of Mann. Our current head of state is Queen Elizabeth II, but only in her role of Lord of Mann not as Queen. The Celtic god Manannan, or sometimes Mannan, is closely associated with the island, so given the close similarity in Gaelic that seems the most likely origin.
The mist that often gathers around the island is known as Manannan's cloak, which legend says he used to protect the island from invaders. One of the two ferries that serves the island is called Manannan and one of the main museums is the House of Manannan. There are well-known statues of him carved from large tree-trunks on the island. There is quite a lot of folklore on the island, including Fairy Bridge, where you have to say hello to the local fairies (Celtic Fairies, not English) as you pass or Bad Things Will Happen. Speaking from personal experience I can confirm this appears to be completely true!
https://en.wikipedia.org/wiki/Fairy_Bridge_(Isle_of_Man)