[Alpha]

On http://www.aena.es/csee/ccurl/LE_ENR_5_4_en.pdf, there is a list of airtraffic obstacles in Spain available. According to this list, at 38°04'36"N 00°39'49"W, there should stand a 370 metres tall guyed mast, which would be the second tallest structure in European Union today. However, when checking the site by Wikimapia, there is nothing, but at 38°4'19"N -0°39'53"E, there is a guyed mast, called "Torreta de Guardamar".

I do not know it, but is it really 370 metres tall?

[minamacmac]

There is indeed a tower in Guardamar del Segura and it does stand 370m high, the sign at the tower actually states 380m.
There are pictures of the tower on this page http://www.cyberia-internet-cafe-guardamar-del-segura.com/places_of_interest.html including a location map.

[Studebaker_red]

I was in the Navy and stationed at that base from 1967 to 1969. At that time, the antenna (Quarter-wave, Marconi) was the tallest man-made structure in Europe at 1290 feet. Sometime in the 1970's the U.N. took it over. And since, I think the Spanish government operates it, but not sure.
It was used for submarine fleet broadcast when I was there and operated at approximately 150kHz. Full power was 500,000 Watts, but we usually ran it at around 25kW to avoid interference with a station in France.