An officially measured 5 mile route on the pedestrian accessways on the 'old' Severn Bridge at night. You really can't get lost and the route is entirely on tarmac. It's generally well lit (but we recommend you use a torch to both make yourself more visible and to pick out features on the ground in one or two places).
Chepstow Rugby Football Club, Burnt Barn Rd, Bulwark, Chepstow NP16 5UP, UK, NP16 5UP
Rogueruns offer you running events with a difference, by runners, for runners