Generally speaking, holidays are held at the time stipulated by the state, unless there are special reasons, it depends on the situation at that time.

National Day is a national statutory holiday to commemorate the country itself. They are usually the independence of this country, the signing of the constitution, the birthday of the head of state or other significant anniversaries; Some are saints' day, the patron saint of this country.

Although most countries have similar anniversaries, due to complicated political relations, this festival in some countries cannot be a national day. For example, the United States only has independence day and no national day, but the two have the same meaning.