A hologram is an object made entirely of light that can be viewed from different angles like a physical object but has no mass or physical resistance. Holograms can be two-dimensional like paper or three-dimensional like real objects. Microsoft Hololens allows users to see and interact with holograms in the real world by pinning digital content and apps virtually anywhere using advanced sensors and a holographic processing unit. Potential uses of Hololens include viewing and editing 3D models, video chatting, gaming, controlling devices remotely, and more across industries like design, manufacturing, education, and healthcare.