Nearly every country has a national day. Here's what they represent

Every country in the world - apart from two - has its own national day and, despite each country having a unique history, national days are commemorated for similar reasons.

National days exist in almost every country to foster a sense of unity, belonging and cohesion.

Key Points

• Australia's national day will take place on 26 January.
• Only two countries in the world don't celebrate national days.
• The national days of most countries commemorate independence from a former European colonial power.

Australia Day, which falls on 26 January, has been a national public holiday since 1994.

It marks the day British ships arrived in Sydney Cove, in what is now NSW, in 1788 and raised the Union Flag for the first time.

Some Australians believe it's a day to celebrate but for others, including many First Nations people, the day is one of mourning and reflection.

Almost every country has a national day and, despite each country having a unique history, national days are commemorated for similar reasons.

Why do countries have national days?

National days remind people of their "sense of belonging to the idea of a nation and what it represents", says historian and researcher Samantha Owen from Curtin University.

Typically, the date chosen for a national day marks a turning point in a country's history that helped solidify its national identity.

"For national holidays to be successful, they rely on consensus to be maintained among those who are citizens that the date chosen, and the thing that's celebrated related to that date, is the best representation of what [the] nation is," she said.

Are there any countries that don't have official national days?

There are only two countries in the world that don't have official national days: the United Kingdom and Denmark.

For the first half of the 20th century, the UK celebrated Empire Day on 24 May, but partly due to changing attitudes to the British Empire it was dropped in 1958.

Denmark has an unofficial national day on 5 June, which commemorates the signing of the Danish constitution.

The United Kingdom and Denmark are the only two countries in the world that don't have national days.

Are national days the same as independence days?

Many countries around the world — including the United States, India and Chile — celebrate national days that mark their independence from European colonial powers.

However, some countries' national days aren't held on that date.

For instance, Bhutan doesn't celebrate the day it gained independence in 1949 as its national day. Instead, it celebrates the anniversary of King Ugyen Wanchuck’s coronation in 1907.

The United States, Chile and India are some of the many countries whose national days are also their independence days.

Many national days celebrate revolutions

After independence days, anniversaries of revolutions or key events that happened during revolutions are the next most common dates for national days.

France’s national day on 14 July, also known as Bastille Day, marks the storming of the Bastille, a French military fortress and prison, which officially marked the start of the French Revolution and ultimately led to the establishment of the first French Republic.

Some countries celebrate their national day on a date that marks the unification of the country or a date of significant political change. Canada's national day falls on the date that three Canadian provinces formed the Dominion of Canada, on 1 July 1867.

Freedom Day is South Africa’s national day, which takes place on 27 April, marking the country’s first post-apartheid elections and the introduction of the new constitution.

France, South Africa and Canada all mark their national days on dates that either commemorate a revolution or a unifying moment for the nation.

What do other national days represent?

The national days of Thailand and the Netherlands are linked to the ruling monarch’s birthday, meaning the dates change along with the succession of a new monarch.

Portugal's national day falls on 10 June, the date on which literacy advocate and Portugal’s national poet Luis de Camoes died in 1580.

The Spanish mark their national day by celebrating Fiesta Nacional de España on 12 October, the date Columbus set sail for the Americas, which has come under increased criticism in recent years, especially in Latin America.

Greenland holds its national day on June 21, "the longest and thus brightest day of the year" and "a natural choice" for the island between the Arctic and Atlantic oceans, the government of the autonomous territory of Denmark says.

Spain, Portugal and Thailand have national days that commemorate a different type of event than most other countries.

Are national days still important?

While national days are supposed to be cause for celebration, they also “draw attention to what's good and what's not good about a state”, said Dominic O’Sullivan, a professor in comparative Indigenous politics and public policy at Charles Sturt University.

“Whether they're days of celebration, or whether they're days of contest, or in many cases, a bit of both, they raise the question of 'what do we mean by nation?'" O’Sullivan said.

- Additional reporting by Rachael Knowles, Rayane Tamer and Isabelle Lane