my room is in a daylight basement with thick cement walls on two sides. my ceiling is about a half meter above ground level, then there is a window, then its all dirt behind the cement wall. the property itself butts against an 80 foot drop right onto the surface of I84. ODOT build a HUGE cement wall to hold up the neighborhood and clear the way for the highway. As I lie half awake in my bed, happy that the snow has cancelled school today, i thought the wall in my room is similar to the freeway wall. all we have to do is dig. what if a tunnel were dug straight down until it reached the groundlevel of the freeway? there'd be this wall to use and a whole nother floor could be built. Or even 7 other floors if you want to use all the space. It'd be so stealthy. The top hole would be for construction, ventilation, and an emergency exit. There would be tunnels going horizontally from the bottom floor for regular access, probably opening into a large culvert or out the side of a hill near the freeway. There is lots of mini plots of land that belong to the freeway but are just grass, too small for a house. A door could be hidden there. Constructing the floor without having 70 feet of earth crush you like a bug would be hard. And if the floor were to ever collapse in the future, the house or maybe houses above would literally drop 8 feet. that would be bad. But hey, Im underground right now and its an awesome use of space. I was suprized to learn that a basement is pretty rare on my block.