Second Life is a 3D virtual world where users create avatars to represent themselves and generate all content. Users can explore, create, and socialize for free or gain additional abilities like owning land by paying a monthly subscription. Universities are using Second Life for classes in subjects like art, science, and medicine by developing virtual environments where students can practice skills like diagnosis. Compared to traditional online classes, Second Life allows for richer experiences through visuals, sounds, and simulations.