All around the world, people are coming and going. How we travel depends on where we live. In Flint, Michigan, many people travel by car. But in Huatajata, Bolivia, on the shores of Lake Titicaca, people might travel by Totora, a crescent-shaped reed boat, as the Uru people have been doing for thousands of years. In Mijas, Spain, passengers are carried by burro taxi as they make their way through the narrow, cobbled streets of the village; while in...