Wade’s Causeway is fabulous cycling country near Goathland, in the North York Moors. South of the village, follow signs to the ‘Roman Road (footpath)’. The lane becomes a bridleway, which becomes a footpath by the time you reach Wade’s Causeway.
And what is it doing up here, and why is it not straight? It doesn’t seem to go anywhere. Was it some sort of training road, or engineering exercise? Nobody is sure.
Cycling on would be physically possible if extremely uncomfortable, but is in any case prohibited. But there’s a good information board, helpfully informing you that expert consensus believes the road is either (a) post-Roman, (b) pre-Roman, or else (c) Roman.