• Legend: Adolf Hitler invented / initiated / built the first Autobahn
  • Truth: The first Autobahn was initiated by later Federal German Chancellor Konrad Adenauer when he was mayor of Cologne. The highway with separated lanes for each direction and grade-separated junctions was opened in 1932 and connected the cities of Cologne and Bonn. After many upgrades, the section is still in operation as the Bundesautobahn A555.
  • The AVUS in Berlin built after the same principles opened in 1921. However, it was a racetrack and car testing facility and not a public road.
  • The word Autobahn was coined by engineer Robert Otzen in 1929, who wanted to replace the awquard expression "Nur-Auto-Straße" (Car-only-road). In 1926, Otzen had founded a society to plan a car-only-road connecting Hamburg with Basel via Frankfurt (HaFraBa). Focus was on freight transport and long-distance bus connections; cars were considered of minor importance.
  • The Nazis were initially against the project. But when they saw the general idea becoming increasingly popular, they claimed full credit, prohibiting the abbreviation HaFraBa to be mentioned publicly. The Autobahn was to be called "Die Straßen des Führers". This propaganda coup stuck with the people and led to the wide-spread myth that Adolf Hitler invented the Autobahn. He didn't, nor did the Nazis.

Die Bundesautobahn 81 (A 81) is a motorway in Germany, branching off the A 3 at the Würzburg-West triangle and ends near the border with Switzerland. Its oldest part between the Weinsberg intersection (A 6) near Heilbronn and the Leonberg triangle (A 8) near Stuttgart was finished in the years 1938 to 1940. This section included the first tunnel built for an Autobahn, the 300 m long Engelberg tunnel. When Weinsberg-Leonberg was upgraded to 3+3 lanes in the 1970s, the tunnel with its 2 lanes each and steep grades (up to 6%) became something of a bottleneck. In 1999, the new 2,530 m long Engelberg tunnel was opened.