Once upon a time, you could drive from the Loop to Santa Monica on one long street. That was Route 66, established in 1926, part of the first batch of numbered interstate freeways. When intact, the two-lane highway was 2,400 miles long, starting its westward path in Chicago (along Ogden Avenue) and carving through Illinois to St. Louis, then across Missouri, a sliver of Kansas, Oklahoma, the Texas Panhandle, New Mexico, and Arizona before finally landing in California.