On the other hand, you get to see the sunset, the twilight, the moon-reflections and the bats, and hear the owls calling across the river.
I think the camera has exaggerated the darkness in these next two photos for effect.
Yes, it's Calstock Viaduct again. As viaducts go, it's a particularly well-located one.
This is an abandoned village and port called New Quay. There was just enough light to still see the huge granite walls of the old quayside and the roofless houses as we paddled past
But as we came up to Morwellham Quay, the light had almost gone.
It was time to turn around.
We slipped secretly back past houses in the darkness, peering in through the lit windows like a stealthy swan, albeit one with rather stiff and aching arms.