Since the advent of the automobile in the early 20th century, American tourism has been largely defined by the idea of the open road. Following WWII, the golden age of the automobile industry and the expansion of the interstate highway system made road-tripping the predominant mode of leisure travel. The format became a key component of American culture. Roadtrips let you experience the Americana of the 1950s and 60s on Route 66. Or explore the rocky coastlines of California on the Pacific Coast Highway, or traverse the Atlantic coast of Florida on State Road A1A. With the largest road network in the world there are thousands of trips to take on US highways and byways, and these are some of the best.