It turns out that Second Life (SL) is a MUVE (Multi-User Virtual Environment). In every-day language, MUVEs are 3D virtual worlds that exist on server space. Second Life was created in 2003 by Philip Rosedale and his team of Linden Lab employees, based in California.
Essentially, SL is a world built entirely by its Residents (users who inhabit SL). This world consists of a Mainland and many Islands. Each island is about 65,000 sq. m (approximately 16 acres). There are approximately 65,000 islands inhabited by approximately 8 million Residents world-wide. There are approximately 50,000 Residents logged in world-wide at any given time.
Islands (also known as "Sims") may be purchased by individuals, organizations or corporations.
Spaceport Alpha: International Spaceflight Museum. This sim contains scaled replicas of a variety of spacecraft, including a Space Shuttle, Vehicle Assembly Building and the International Space Station.
The Ann Myers Medical Center is a sim dedicated to the furtherance of interactive collaborative medical training.
There are many sims in SL which house a variety of venues design for education and meetings:
For Residents interested in creating and leaving their mark in SL, there are a variety of tools they may use to build, as well as tutorials and building classes. In addition to building, Residents may learn to script (program) an SL-specific language, Linden Scripting Language (LSL).
The most proficient of builders and scripters produce landscaped sims such as the one below, produced by The Magicians, a real-world company for hire which builds and scripts within SL: