Active Worlds 5.1

Activeworlds offers a complete range of user, client, server, and development applications that make it simple for everyone to get involved in creating and enjoying the best 3D content on the Internet.
To date, over half a billion objects have been created by the incredible ActiveWorlds community. Alphaworld, the worlds largest 3d virtual world in existence, has land space that is larger than the State of California. In ActiveWorlds you can chat in 3d worlds, build your own virtual world in minutes, or customize your avatar with thousands of possibilities.