The flag of Spain symbolizes the nation, and is sign of its sovereignty, independence, unity, integrity, and promise of its perpetuity through the times. The national flag is regulated by article 4 of the Spanish Constitution:

The flag of Spain is formed by three horizontal stripes, red, yellow and red, being the yellow of double width than each of the red ones.
 
 
 
 
 
 

The coat of arms of Spain is regulated by Law 33-1981, of October 5: 

The coat of arms of Spain is divided quaterly. In the first party, a gold castle on a gules or red field represents the kingdom of Castile. In the second party, a purple, rampant lion crowned of gold on a silver field represents the kingdom of Leon. In the third party, four red pales on a gold field represent the kingdom of Aragón. In the fourth party, a gold chain on a red field represents the kingdom of Navarre. At the tip of the shield, a pomegranate with two vert or green leaves on a silver field represents the kingdom of Granada. The shield is accompanied by two silver columns with gold bases and capitals, on waves of blue and silver, topped the one on the right by an imperial crown and the one on the left by a royal crown, both of gold. Surrounding those columns, there is a red ribbon with gold letters, reading "PLVS" on the right and "VLTRA" on the left. Embedded in the main shield there is a smaller one: three gold fleurs de lis on a blue field with red border represent the reining dynasty (Bourbon or Borbón). The shield is topped by a royal crown, which is a gold circle encased with precious stones, and made up of eight fleurons of acanthus leaves, visible five, interpolated of pearls. A diadem of pearls emerges from each fleuron, all converging in a globe of blue with a gold half-meridian, equator, and cross. The crown is lined in red.

Historians and musicologists agree that at the root of the Spanish national anthem is the Grenadier March (Marcha Granadera), although Father Otaño believes it originated much earlier, from the debatable hypothesis that song number 42 of Alfonso X's "Cantigas" ("Songs") contains a sentence of the anthem.

In 1761, Manuel Espinosa wrote the "Book of Ordinance of Military Music for the Spanish Infantry", in which the March appears as having unknown author.

King Carlos III declared it March of Honor on September 3, 1770, and it soon acquired status of national anthem, without written disposition.

In 1870, General Prim organized a national contest to create an official anthem for Spain, but the jury declared no winner and advised to continue using the Grenadier March as the national anthem.

A law of August 27, 1908 instructed military bands to play the so called Royal March, regulated by Maestro Bartolomé Pérez Casas, of the Royal Corp of Guards Halberdiers.

A law passed on July 17, 1942 declared the Grenadier March the national anthem of Spain, without including any score, thus keeping the version of Pérez Casas.

After the approval of the Spanish Constitution on December of 1978, 27 president Suarez established a task force integrated by members of the Section of Music of the Royal Academy of Fine Arts of San Fernando and representatives of the Ministries of Economy and Treasury, Education and Culture, Defense, and Public Administrations to write a new version of the anthem. After the favorable report of the Royal Academy, a new adaptation authored by Maestro D. Francisco Grau, director of the Royal Band, was approved. 

The national anthem of Spain has no lyrics.

During most of its history the national anthem of Spain has had no lyrics. In June, 2007 the Spanish Olympic Committee (COE) proposed a contest to select lyrics for the anthem. The selection committee chose the following lyrics by Paulino Cubero in January, 2008:

¡Viva España!
         Long live Spain!
Cantemos todos juntos
         Let's all sing together
con distinta voz
         with different voices
y un solo corazón.
         and a single heart.

¡Viva España!
         Long live Spain!
Desde los verdes valles
         From the green valleys
al inmenso mar,
         To the endless sea,
un himno de hermandad.
         an anthem of brotherhood.

Ama a la patria
         Love the fatherland
pues sabe abrazar,
         that embraces
bajo su cielo azul,
         under its blue sky
pueblos en libertad.
         free peoples.

Gloria a los hijos
         Glory to the sons
que a la Historia dan
         who gave History
justicia y grandeza
         justice and greatness,
democracia y paz.
         democracy and peace.

The COE had planned to collect the necessary signatures (more than 500,000) to propose the lyrics as the official anthem of Spain as a popular initiative. However, and due to the lukewarm reaction to the proposal, it decided to withdraw the lyrics.

Listen to the Spanish National Anthem in MP3 y MIDI formats.

A convention to draft a new constitution convened on the 22nd of August, 1978 with representatives from all the political parties. There were difficulties reaching consensus on issues such as education, abortion, death penalty, and socioeconomic matters, due to differences between the two main parties (centrists and socialists). However, an agreement was reached and cemented by the creation of a Constitutional Court responsible for the interpretation of the Constitution. The final text was approved by a public referendum on December 6th, 1978 with 88% of the votes. The most important achievement of the Spanish Constitution of 1978 is that it has resolved some of the historical problems that hung over the Spanish people for over a century.

Text of the Spanish Constitution of 1978