Now that you've had a chance to see and read about the history of Netscape Navigator's journey to public release, experience it for yourself. Pre-1.0 versions of Mosaic NetScape/Netscape/Netscape Navigator are available for download directly from this site:
Mosaic Netscape 0.9 for Macintosh
Please appreciate that whereas Netscape 0.93 through 0.96 for the Mac still exist other places on the net, you won't find version 0.9 (first public release) anywhere but here - at least as of 3 January 2000. If you choose to download version 0.9, you'll need to set the year of your computer as "1994" so that the beta works.
If you're looking for other versions of Netscape Navigator, you'll find them off-site in the browser archive section of evolt.org.