Why was Route 66 called 'America's Main Street' and which different cities did it pass through?

Answer: Over the years, US 66 received numerous nicknames. Right after US 66 was commissioned, it was known as "The Great Diagonal Way" because the Chicago-to-Oklahoma City stretch ran northeast to southwest. Later, US 66 was advertised by the U. S. Highway 66 Association as "The Main Street of America".