It took about three hours to get to Machu Picchu from the town of Cusco by train, but I was not bored. It is because the train ride was along a mini "yellow river" and the chocolate-like current is a very interesting view. I could not use a tripod to do a long exposure on the train, of course. Rather, I took the pictures after the train reached the destination. Unfortunately, I didn't expect to see this river and thus both of my neutral density filter and polarizer, which can cut down the light to prolong the exposure for the silk-like effect, was not put into the camera bag. I was forced to use a smaller aperture (e.g. f-22) and consequently sharpness was compromised.