I was watching Time Team on the ABC where they were excavating a suspected crannog and henge monument at Loch Migdale in Scotland back in 2004 when they showed a quick bit of video of the remains of a stone causeway underwater.
Whilst watching the fly over of the rocks something caught my eye, something that looked too regular to be natural and what appeared to me to be a round circular container. I had recorded it on the DVD recorder so I grabbed a few frames to show, but whilst it can be hard to see in still images it’s a bit more obvious when you see it moving so I’ve also got an animated GIF of those put together here.