This morning we drove to Williams, and from there caught the historic Grand Canyon Railway train to the South Rim of the Grand Canyon. Like Monument Valley, we have all seen the images, and then so frequently, but nothing can prepare you for the reality. It is not just the width and the depth of the canyon, nor the beauty of the striations and rock formations but, rather, the enormity of the whole site and of the time scale taken to create it – mainly through erosion by the waters of the Colorado River (which is occasionally visible a mile below) over a period of some 17 million years. But even that timescale pales into insignificance in comparison with the age of the 2 billion year old Vishnu Schist rock at the bottom of the Inner Gorge. We walked the trail around the South Rim (getting caught by a very impressive sudden storm on the way) and so were able to follow a series of information panels accompanied by samples of rocks taken from every stratum in the canyon. Millions and billions of years are beyond my true understanding and I left the site, as I had left the Imax cinema at the Smithsonian in Washington, feeling humbled. On the train journey back we saw a herd of elk and another very impressive storm. I shall pass over the two hour wait for our Amtrak train to materialise. By midnight we were in our sleeper car on the way to California.