Here is my stab at architectural photography. Here's a definition of leading line that I found online. "Leading lines refers to a technique of composition where the viewer of your photos attention is drawn to lines that lead to the main subject of the image."
I love leading lines because they visually guide the reader somewhere. This process happens without our even knowing it. For example, it probably happened to you when you first saw the picture. Your eyes started at the bottom of the picture and were lead along sidewalk, caged in by the pillars to the window at the back of the hallway. I find this so fascinating.