A: Lexington, Massachusetts, United States
Ivan Sutherland demonstrating Sketchpad. The image is a 50% reduction of 4 thumbnails of a low resolution video.
In 1963 Ivan Sutherland, a student at MIT's Lincoln Laboratory in Lexington, Massachusetts, working on the experimental TX- 2 computer, created the first graphical user interface, or first interactive graphics program, in his Ph.D. thesis, Sketchpad: A Man-Machine Graphical Communication System.
Sketchpad was an early application of vector graphics.