To begin working on the Twin Towers, we must first mark our horizon line and vanishing points. We will be using two point perspective. Because of the angle we will be working at, you will need a wide sheet of paper in order to mark your vanishing points properly. Since there are two towers, it is important to understand that they to not share the same vanishing points. Each tower has it's own set of vanishing points. In this case, I have marked the vanishing points for 1 World Trade Center in blue, and 2 World Trade Center in green. They are close to one another along the horizon line, but they do not touch.