Blake Shelton’s ‘God’s Country’ plays on the radio as bolts of lightning tear through dark clouds, illuminating the corn fields of the Midwest. ‘Slow down,’ demands Mum, clutching her seat. It’s clear she’s grateful the rental company did not give me the muscle car that I was hoping for. We’re on America’s ‘Mother Road’, otherwise known as Route 66. Or what’s left of it that is. The original highway ran 2,448 miles cross-country from the city of Chicago, Illinois, to the beaches of Santa Monica in California, but was replaced in the 1950s by the Interstate. Although 66 is no longer still officially a highway, and you can’t drive along the entire original course, the majority – around 80 per cent – of the sections have been preserved and renamed ‘Historic Route 66’.