Because the Western calendar starts with Year 1, and not Year
0, the 21st Century and the Third Millennium do not begin until January
1, 2001. Though some people have great difficulty in grasping this, there's
a very simple analogy which should appeal to everyone. If the scale on your
grocer's weighing machine began at 1 instead of 0, would you be happy when
he claimed he'd sold you 10 kg of tea?
- Arthur C. Clarke
From the January, 1900 issue of Scientific American:
"In the daily press we find a fierce epistolary (letter writing) battle raging between those who believe that the year 1899 marks the close of the nineteenth century and those who hold that not until 1901 shall we cross the threshold to the new era. It seems so difficult to understand that 1800, 1900, and 2000, designates not the beginning, but the end of a century. It is evident that there was never a year 0, that the century must begin with a 1. A hundred years ago the same wordy war was raged; a hundred years hence it will be renewed."
For many, many more links to pages dealing with this vexing case of cultural obtuseness, click here.
(Courtesy of Phil Konstantin, who compiled it.)