Margen
When the Spanish anthem plays, the players don't sing because there is nothing to sing. The Marcha Real is one of the very few national anthems in the world without official lyrics — alongside those of San Marino, Bosnia and Herzegovina, and Kosovo — and not because they got lost along the way: in more than two and a half centuries it has never had any.
The melody is first documented in 1761, in a book of military bugle and drum calls, as the «Grenadier March». Nobody even knows for certain who composed it.
Lyrics, on the other hand, there have been plenty: under Alfonso XIII a version by Eduardo Marquina was sung; under Franco, another by José María Pemán. None was ever official, and each fell with its era. The last attempt came in 2008: the Spanish Olympic Committee picked a winning text from thousands of entries, controversy erupted within hours, and it was withdrawn within days.
So Spain competes with an anthem you can only hum. That «lo-lo-lo» in the stadiums isn't apathy: it is, quite literally, all there is.