From Wikipedia:

In pre-Christian Rome under the Julian calendar, the day was dedicated to Janus, god of gateways and beginnings, for whom January is also named. From Roman times until the middle of the eighteenth century, the new year was celebrated at various stages and in various parts of Christian Europe on 25 December, on 1 March, on 25 March and on the movable feast of Easter.^[2][3]

In the present day, with most countries now using the Gregorian calendar as their civil calendar, 1 January according to that calendar is among the most celebrated public holidays in the world, often observed with fireworks at the stroke of midnight as the new year starts in each time zone. Other global New Year's Day traditions include making New Year's resolutions and calling one's friends and family.^[1]