The Day of the Spanish Constitution is a public holiday celebrated in Spain since 1983 and commemorates the referendum on the Spanish Constitution held on December 6th 1978.
Obviously as the day is a public holiday, Catalans take the day off and the day often marks the start of a three-day pre-Christmas break as December 8th is another public holiday known as La Purissima.
Many people in Catalonia also take the day in between off work in what is known as a pont or bridge.
However, the Day of the Spanish Constitution is not celebrated with much enthusiasm here and much like on El Dia de la Hispanitat, the televised parades and shows of strength by the Spanish Armed Forces in Madrid provoke little interest.
Although the Catalan people voted overwhelmingly in favour of the Constitution in 1978 during Spain's Transition to Democracy after the death of General Franco in 1975, the document is now generally seen as not being particularly favourable to Catalonia.
The Spanish Constitution, which describes national sovereignty as residing in the indissoluble unity of the Spanish people, has frequently been used by the Spanish Government in recent years as the reason for not allowing Catalonia to hold a referendum in order to decide its political future.
The fact that the 1978 Constitution also describes Catalonia as a Nationality rather than a Nation led to the Spanish Constitutional Court rejecting parts of the Statute of Autonomy of 2006, which in turn led to the current upsurge of calls for Independence for Catalonia.