One of the Story of the World activities we did was to recreate cave drawings. I used a black sheet and hung it up across our hallway to create a cave. This worked perfectly as the sheet hung down in the back creating an opening on one end and wall space on either side.
I taped pieces of brown paper to the wall on either side. I smashed the paper into a ball then flattened it back out to create a rougher surface that replicates rock.
The boys got to work thinking up ideas.
I'm laying on the floor at the point looking in the door, you can see the sheet hanging down behind the boys. It was really neat, A has asked for a cave several times since then just to play in.
They snuck flashlights in at one point. I had to explain to them how historically inaccurate that was.
Here's some of the finished drawings.