Welthauptstadt Germania or “World Capital Germania”. it was a renewal project for German capital Berlin during Nazi period, as per Hitler’s vision for the future of Nazi and the planned victory in World war 2. Albert Speer, was the architect of the planning the vision of Hitler.
The creation of a great East-West city axis, and placing the Berlin victory column in the center, far away from the Reich stag, where it originally stood, were completed, while the rest were cancelled due to loss in war.
“As world capital Berlin will only be comparable with Ancient Egypt, Babylon, and Rome! What is London, what is Paris compared to that!”
— Werner Jochmann: Adolf Hitler. Monologe im Führerhauptquartier 1941–1944, p. 318. Munich, 1980.
They even proposed World War Arch Of Triumph at the end of southern end of the avenue.
If Nazi would have won and completed the vision of Hitler, Berlin would have been something like above picture.
image 2: https://www.google.co.in/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&ved=0ahUKEwihzqKQ2d_RAhUMqI8KHVCtBwgQjBwIBA&url=http%3A%2F%2Fi.imgur.com%2FF6uoQ.jpg&psig=AFQjCNEisz3-mVI1XAIm7itCMKHEmGOX3A&ust=1485516170965001
image 4: http://www.9gag.com