Check out this fun visual history of Mac OS X/macOS

GitTower, which makes the Tower Git client, is celebrating the launch of macOS Sierra with an update of its info site, An Illustrated History of macOS.  

It offers a fun visual journey through Apple's operating system for the Mac. The site starts with Mac OS X Kodiak, which debuted in September 2000, down through the recently-released macOS Sierra. Check out “An Illustrated History of macOS.” I think you’ll enjoy it.