A building block may be designed to hold utilities, including but not limited to, electricity and plumbing. Such a building block can resist compression forces and moment and can connect to other building blocks to form a modular wall system with the ability to distribute the forces in a way that reduces the stresses on each individual block. The building block may include a body with an upper end and a lower end, one or more main compartments, and one or more inner pass-through openings, wherein the upper end includes one or more protrusions, and the lower end comprises one or more intrusions and one or more slots. A building system may include more than one such building blocks and a base.