1. Virtual reality is an artificial 3D environment that is created with software and presented to users in a way that makes them feel like they are experiencing a real environment. 2. Early VR systems included head mounted displays, tracking systems, and input devices. Modern VR uses these components along with powerful computers and sophisticated sensors. 3. VR has applications in many fields including gaming, product design, architecture, medicine, and more. However, challenges remain around creating realistic environments, avoiding health issues, and developing natural human interaction.