I stumbled upon this in the 2nd floor stairwell of the Art Department at the university. It appears to be charcoal or graphite or both. It looked like it was more than 6 feet wide and around 10 feet tall...hanging on the wall. It's not a mural but a canvas with a fixative or sealant of some kind. I was amazed at some of the shading. I could not figure out what the seams were. They may have been creases where it was folded in order to move it.
A closer look at the top of the canvas. Notice how some of the people figures in the drawing are "drawing the drawing." My speculation is that like other works of art on display in the Art Department, this was made by students. Notice also the arm of the large figure reaching out like that of Michelangelo's Creation of Adam.
This shot shows the canvas in the stairwell and gives a bit of perspective of the size. What is amazing to me is how a limited amount of media in talented hands can be so expressive.