Abstract: In one embodiment, the present invention can include a foldable structure employing material-filled panels which can be used as an emergency shelter in disaster areas. A building can formed from one or more building blocks. The building blocks can be in a compact position, such as when being transported to a disaster area, or in an expanded position, such as when the building is ready to be built in the disaster area. In the expanded position, the building blocks can be filled with various materials such as expanding foam material. The expanding foam material can be formed from two mixing materials. In addition, the expanding foam material can have insulating properties. The building of the present invention can also be used, for example, as sheds, tree houses, and/or permanent housing. The building blocks can have marine applications and/or military application due to their light weight, yet, ballistic nature.