Virtual reality (VR) uses computer technology to create a simulated environment that replaces the real world, stimulating the user's vision and hearing. It can be used for virtual travel, immersive training, storytelling, gaming, and therapy. Popular VR headsets include the Oculus, HTC Vive, Samsung Gear VR, and Microsoft HoloLens. Augmented reality (AR) enhances the real world by overlaying digital content and information. It is used in apps on mobile devices and upcoming technologies like smart glasses. While VR creates a fully digital environment, AR blends the digital with the physical world. Popular AR devices include smartphones, tablets, and headsets like the Microsoft HoloLens.