You'll probably be even more annoyed that you missed walking on Devil's Dyke, Fleam Dyke and the Roman Road out of Cambridge. It's my marathon training ground and I think it's a huge privilege to run through this landscape. Going from the chalk near Cambridge onto the clays of Suffolk you see the vegetation and wildlife change. I can stand on Mutlow Hill and imagine all the people who have stood in the same spot over the past 1,200 years. It's inspiring.