Windows Longhorn was meant to be the successor of Windows XP, and was a development project by Microsoft which got away from the company, increasing constantly in scope and ambitious, to the degree that in the end Microsoft had to cancel it and replace it with Windows Vista.

Because it was never released, and the plans so ambitious, there is a certain mysticism about the operating system and what could have been.

Those who remember the hype may appreciate a look at the login screen of the cancelled operating system, posted by the Beta Collector account, run by Stephen Chapman, who is trying to preserve Microsoft memorabilia.

The above was originally demoed by Hillel Cooperman at PDC 2003, which can be seen below:

Ironically as the power of our PCs have increased, the graphical features of the operating system have only decreased, meaning Windows Longhorn was really a view of an imagined future which was never meant to be.