Stronsay, a storm-lashed, remote corner of these isles was the scene of one of the most enduring mysteries of the sea when a huge, mysterious and still-contentious body was washed ashore.
Today classified as a "globster" - a rotten mass of collagen and blubber from a dead sea creature such as a whale - the beast still throws up some mysteries that defy easy explanation.
The official identity of the beast is a decayed corpse of a basking shark - set in stone by investigators later in the 19th century who declared that the beast was 36 feet in length. However, measurements at the time set the length at 55ft - far bigger than the biggest basking shark, which only attain a length of around 40ft.
Another minor and unexplained detail were the 'bristles' which coated much of the body. If the globster theory is correct, then these are explicable in those terms, but why they were reported to glow in the dark is not.