Distance education, also known as distance learning, is the education of students who may not always be physically present at school, or where the learner and the teacher are separated in both time and distance. Traditionally, this usually involved correspondence courses wherein the student corresponded with the school via mail. Distance education is a technology-mediated modality and has evolved with the evolution of technologies such as video conferencing, TV, and the Internet. Today, it usually involves online education and the learning is usually mediated by some form of technology. A distance learning program can either be completely a remote learning, or a combination of both online learning and traditional offline classroom instruction. Other modalities include distance learning with complementary virtual environment or teaching in virtual environment (e-learning).