Clach an Truseil is the tallest monolith in Scotland — a single standing stone of Lewisian gneiss rising 6 metres from the moorland near the village of Balantrushal on the northwest coast of Lewis. It dates from around 3000 BC. Unlike Callanish, which is a formal stone circle with good interpretation, Clach an Truseil stands alone in a field, with no fence around it and no signage beyond a small roadside marker.
The lack of spectacle is part of the point: a rock from the Bronze Age, still standing, with sheep grazing around it and the Atlantic visible in the distance. The stone leans slightly — it has been doing so for at least several centuries — but shows no sign of falling. You can touch it and stand next to it. It is accessible from a pull-in on the A857 road, about 25 kilometres north of Stornoway.