Everyone (or almost everyone) celebrates the ending of the old year and the beginning of the new year, at different times and under different names. Starting in some 12 hours, there will be celebration round the earth of the common new year, which is far from the primary new year for everyone: other new years are spread over the year, some wandering and some more or less fixed, the latter occurring for most within the next four months.
Just a few curiosities concerning the common new year;
The strange positioning of the common new year occurring between the 31st December and the 1st January in the common calendar can be blamed on the second king of Rome who muddled up the original Roman calendar which began with Martius and included the spring equinox, adding two months at the wrong end which is evident by the fact that the months September - December which literally stand for the seventh - tenth months became the ninth - twelfth months.
And the turn of the millennium occurred between the 31st December 2000 and the 1st January 2001.
But whichever way you see it: Happy Whatever to whomever whenever.