advantage, was of course possible in OS X, but it required entirely rewriting an application. So Apple provided an environment to which old Mac apps were easy to port, called Carbon — and OS X even supported those apps natively in a third environment, called Classic. Although Classic could not support any of OS X’s benefits, it was necessary to ease the radical transition from the old Mac OS to the brand new OS X.

Aqua was a revolutionary new user interface that visually took the Mac OS and even NeXTSTEP to a whole new level. It used translucent colors instead of solid grays, circles instead of angles, and shadows and transparency aplenty. In fact the reason it was called Aqua is that “you wanted to lick it”.

Mac OS X shipped on March 24, 2001, and became the core of Apple’s resurgence and current success. What an incredible twist of fate: to make a long history short, Apple was eventually saved by NeXT, a company