John Steinbeck, in his immortal book, The Grapes of Wrath, called Route 66 "The Mother Road."
U.S. Highway 66 was the first road to connect Chicago to Los Angeles. During the Great Depression, it was the way for large numbers of families (like the Joads in The Grapes of Wrath) to escape the Dust Bowl. In better times, it came to symbolize American love of freedom, the automobile, and mobility. Rout 66 was decommissioned in 1988. Many still travel Route 66, not to go anywhere in particular, but to partake in the most famous of all possible road trips. The route is the destination.
Many organizations work to preserve Route 66, the accommodations and attractions that built up around it, and the memory of Joads and the real-life families that looked for a better life. View the websites of the National Park Service Route 66 Preservation Program and the Illinois Route 66 Byway.