which country has no words in it's national anthem?

It's SPAIN.

The "Marcha Real" (Spanish pronunciation: [ˈmaɾtʃa reˈal]; "Royal March") is the national anthem of Spain. It is one of only four national anthems in the world (along with those of Bosnia and Herzegovina, Kosovo, and San Marino) that has no official lyrics. (although it had lyrics in the past, they are no longer used).

History

Though the Marcha Real has no lyrics, words have been written and used for it in the past. One version was used during Alfonso XIII's reign and another during the Francoist State; however, none of them were ever made official. The national anthem has been played without words since 1978, when the lyrics that had been approved by General Francisco Franco were abandoned.

After witnessing a rendition of "You'll Never Walk Alone" at Anfield in 2007, the President of the Spanish Olympic Committee (COE), Alejandro Blanco, said he felt inspired to seek lyrics to "La Marcha Real" ahead of Madrid's bid to host the 2016 Olympic Games. That same year Telecinco, enticed by the COE, organized a National contest and posted 25 different lyrics on their website which they thought best matched COE's requirements. The winner was chosen after 40,000 people voted. The lyrics by Enrique Hernández-Luike, magazine publisher and poet, spoke of freedom, peace and the Constitution. The winning lyrics were sung by the Ronda de Aranzueque choir in Pastrana, and filmed by German television. However, the COE organized a new competition for the lyrics, which resulted in between 2,000 and 7,000 entries (depending on source). A private team of jurors chose the entry by Paulino Cubero, then unemployed. The new lyrics received criticism, resulting in them being pulled only five days later, and the idea was scrapped indefinitely. However, A number of the autonomous communities of Spain have their own regional anthems.