It is called Cherry Island and is what is known as a crannog – a man-made island, probably built around the time of Christ. In the early twentieth century, one of the monks from Fort Augustus used an early diving suit to study its construction, which is mainly substantial trees crisscrossing each other for foundations.
It was constructed as a defensive structure. Some Picts built homes on islands with access walkways to shore. Not only did these provide protection from wild animals and easy access for fishing, but they were also very easy to defend. If an enemy were attacking, firstly they would find it difficult to gain access and, in most cases, would just steal some animals and move on. If however it was a more substantial force, the walkway could be burned, preventing the enemy gaining access at all.
There are many crannogs in Scotland and several have been studied by archaeologists who have found charcoal along the line of the submerged walkways, showing that this tactic had been used on several occasions.
When the Caledonian Canal was constructed, the water level was raised by two metres. This is causing waves to erode Cherry Island and it will one day sink into the loch.