In the United States, 1870 was the year that federal holidays became law. Jan 1st was the earliest in the year. Other countries were later. It only became a bank holiday in the United Kingdom in 1973 after it was pointed out that employees tended not to turn up that day or were inefficient because they were hung over.
New Year's Day is the beginning of the New Year in the Gregorian calendar. Many countries mark the day with unique customs and traditions. London holds one of the most popular fireworks events in the world on New Year's Eve.