I was young and we were having an addition installed on our house. We were in the process of extending our basement. The concrete room was all in place with windows and everything beneath the foundation of our new room, but there were no stairs. Being curious, I climbed down through the window. I was thinking, wow this is awesome, until my mom told me to get out. When I was climbing back out, I slipped and ran my entire left forearm down the concrete. The entire section (about 6 inches) was cut open and bleeding like a sonuvabitch. It had a bunch of deep cuts and the entire section had had the skin scraped away. The wall was actually bloody.