The tiny Pacific Island nations of Samoa and Kiribati were the first places in the world to step into 2020 as millions of people across the world ushered in the New Year with fireworks and celebrations.

Yet, it is not a new year for everyone.

In Ethiopia and China, citizens will have to wait for more days or even months before they can see another year.

The two countries have own calendars unlike the rest of the world which uses the widely followed Gregorian or the Christian calendar.

The Chinese will start their New Year in January 25, 2020 and end on February 11, 2021, according to the Telegraph.

Ethiopia whose calendar is seven to eight years behind the rest of the world celebrates their New Year on September 11 of the Gregorian calendar or September 12 on leap years of the Gregorian calendar.

Also known as the Christian calendar, the Gregorian calendar is a calendar currently used by many people across the world. The calendar has 12 months a year divided into 7 days a week and 365 days a year or 366 days during leap years.

Meanwhile, the Ethiopian calendar has 13 months in a year, 12 of which have 30 days while the 13th month has five days, and six days in a leap year.

The first calendars date back to the Bronze Age around what today is the Middle East. These ancient calendars were generally based on the phases of the moon and the solar year. Since then, various cultures have developed own calendars.

As a result, there remains a number of calendars across the world today; many of them religious based just like the Ethiopian calendar which belongs to the Ethiopian Orthodox Church.

The Gregorian calendar for instance has Christian origins, even though it has been widely adopted by most countries as the default international standard.

The calendar is the broadly accepted “general use” calendar according to which there are 365 days a year, divided into 12 months of fixed and unchanging lengths except during leap years.

The Gregorian calendar's predecessor, the Julian calendar, was replaced because it was astronomically inaccurate.

The calendar was officially introduced in 1582 and named after Pope Gregory XIII, alt-hough it is an adaptation of a calendar designed by Luigi Lilio (also known as Aloysius Lilius), an Italian doctor, astronomer, and philosopher.

The introduction of the calendar was initially met by heavy protests across Europe and other parts of the world before gaining popularity and wide use for its accuracy and convenience in the international trade.

But while many countries and non-Christian communities have accepted the Gregori-an calendar as their international standard for representation of dates and times, they still retain their own calendars for religious purposes.

Other calendars include;

1. The Hebrew calendar

Also known as the Jewish calendar, this was originally created before the year 10 AD. It first utilized lunar months and calendar years, adding an extra month every 3 to 4 years in order to make up for the difference between the two.

Over time, mathematical calculations replaced that system. Today, it is used to deter-mine the dates for Jewish religious holidays, to select appropriate religious readings for the day, and to conduct ceremonial events

2. The Hijri calendar or the Islamic calendar

This calendar is based on lunar phases (movement of the moon). It uses a system of 12 months and either 354 or 355 days every year-during leap years.

The first Islamic year was 622 AD when Muhammad emigrated from Mecca to Medi-na. This system means that the current Islamic year is 1441, corresponding to 2020 on the Gregorian calendar.

The calendar is used to identify Islamic holidays and festivals.

3. The Buddhist calendar

It is widely used in Southeast Asia and is based on an older Hindu calendar.

Although it is not used as an official calendar, the Buddhist calendar is used to mark important festivals.

4. The Chinese calendar

It is based on a lunisolar system. According to this system, each month begins on the day when the moon is in the "new moon" phase.

The beginning of a new year is also marked by the position of the moon and occurs when the moon is midway between the winter solstice and spring equinox.

Whereas China officially uses the Gregorian calendar it uses the Chinese calendar to celebrate holidays.