Hadrian's Wall, UK
A great cycle ride! Train from London to Ravenglass via Carlisle, up the west coast past old Roman ports. Then across the route of the old wall. Big climb into Haltwhistle; Corbridge is a great town; ending in Wallsend, Newcastle. Some great pubs. Then train south to London.
Photos here:
https://www.icloud.com/sharedalbum/#B02G1CvrSGFuyVi