3. We celebrate on Jan. 1 because Julius Caesar said so
Why does the New Year begin on January 1st? Because our contemporary (Gregorian) calendar is based on the Julian one (named after none other than the Big Ceas) and he made January month numero uno (which is latin for "number one" btw).
4. But New Year's used to be on March 20th
The first indication of a new year’s celebrations crop up around 2000 BC in the Middle East. Or, as its known in 9th grade history class, “Mesopotamia". At that time (2000 BC, not 9th grade), each year began on March 20th, AKA the vernal (or Spring) equinox. That's the one where the sun crosses directly over the equator. Nowadays, celebrating New Year’s is illegal in much of the same region (e.g. Saudi Arabia). Fertile crescent? More like festive crescent!