The Autobahn is a very well engineered German highway system. It is well known but was also was constructed during Nazi Germany.
While it was built by evil people, it still is a fantastic highway system that is used today.
Perhaps I should have posted this link first.
Hitler building the (first) Autobahn is a myth constructed by nazi propaganda. Repeating it is just falling for their lies.
That being said of course it is a very important piece of infrastructure today, but that is due to decades of car industry lobbying and the lack of funding for other transportation and transit infrastructure projects. Especially trains would be able to transport more people and goods faster if build properly.