Mosaic

Mosaic was the first 'free' cross platform web browser. This was significant as it made the internet accessible to the people. Mosaic was one of the first browsers to render images inline to the HTML.

Mosiac could also function as an ftp client, gopher client and NNTP.

Windows

Mosaic on Windows required the new Win32s environment to run on. Old versions can be found here

Macintosh

Versions can be found here.

Unix

Compiled versions can be found here. It is somewhat common to have to compile Mosiac on the host platform... It does require motif which can be difficult on 'modern' systems. There is a port to newer Linux systems here.