One of the shelters students spend the night in on the Wilderness Bushcraft Semester is one with no insulation, just a fire to keep warm. This image is from that night a few weeks ago. It is a great learning experience with regard to the use of fire to keep warm, the science involved with the inverse square law, and understanding how much wood one needs to make it through the night. As with many things that we do, the only way to really know is to do it. This epic photo was taken by one of the guys on the course.