Virtual classrooms simulate live classrooms online for synchronous learning. Lessons allow real-time interaction between educators and learners who may be in different locations. Virtual classrooms provide flexibility and accessibility through technologies like videoconferencing, digital whiteboards, and instant messaging. They offer educational continuity when physical classrooms are not possible. Virtual universities provide higher education entirely or partially online to increase access for students who cannot attend campus due to distance or scheduling. They connect learners and instructors through computer networks and eliminate geographical boundaries. Early examples include the Open University of the UK and experiments in the 1980s-90s to conduct international online classes, developing the concept of a global virtual university.