One Point Perspective creates depth using a linear technique. That is, the artist draws all the lines of the painting to meet one point that he or she decided on in advance. In this drawing of a streetscape, all the lines are meeting in the lower right of the drawing, where the street meets the far away city skyline.
This photograph shows the effect that artists are trying to represent in their art using one point perspective. Notice that the buildings in the photograph seem as though they will meet farther down the street even though in reality they are going in parallel, straight lines, and stay the same distance from each other.