Mysterious Lighthouse
Probably my favorite unsolved mystery is the Eilean Mor Lighthouse Mystery. Basically, the three lighthouse keepers disappeared from the island. Inside the lighthouse, they found uneaten meals on the table and missing coats among other weird things. The creepy part is the log book.
It’s supposed to be used strictly for logging work related entries, but they started using it as a sort of journal/diary. It was explained in the log book how there was a terrible storm that was lasting for many days and that one of the keepers, an old, weathered seaman, was crying in fear.
The last entry said that the storm had ended and everything was calm and fine. A neighboring island reported that there was never a storm.
Story Credit: Reddit/angrymoose93