Flannan Isles

Eeee, I do love an archipelago. No better and more remote that the Seven Hunters 30km off the Coast of Lewis; and 100km NE of St.Kilda. The islands are also known as the Flannan Isles [R] and were uninhabited for more than 1000 years between the contraction of the Celtic Church in face of the the onslaught of Northmen out of Scandinavia and the opening of the lighthouse on the plateau of Eilean Mòr [L] at the NE corner of the group. The lighthouse was designed by David Alan Stevenson grandson of Robert Stevenson the engineer. Just to the South of Eilean Mòr is Eilean Taighe the island of the house - a slab-built structure that probably dates from monastic times.  St.Stephen's is the best day to write about Flannan Isles and its lighthouse keepers because that's the day in 1900 when:

Though three men dwell on Flannan Isle
To keep the lamp alight,
As we steer'd under the lee, we caught
No glimmer through the night!
...
And, as into the tiny creek
We stole beneath the hanging crag,
We saw three queer, black, ugly birds--
Too big, by far, in my belief,
For guillemot or shag--
Like seamen sitting bold upright
Upon a half-tide reef:
But, as we near'd, they plunged from sight,
Without a sound, or spurt of white.

by Wilfrid Wilson Gibson

The light had been out since 15th December and the weather was so brutal that the relief vessel the SS Hesperus was unable to go investigate immediately and didn't arrive at the landing-place until the day after Christmas. The three keepers had disappeared!  It was the greatest mystery of the time, the land-based equivalent of the more well-known Marie-Celeste.  With so little data there has been plenty of scope for explanations that lurch off-planet, and a lot of people are happy to believe that the three men went off to father a clutch of little green lighthouse-keepers on the planet Zarrx.