"In a nutshell: land of American oak, increasing ambition, sherry, and low-yielding bush vines...
Proud possessor of more land devoted to vines than any other... Spain is an anarchic jumble of districts and regions... A look at a map suggests just how much climatic diversity there is likely to be between Spain's many wine regions, from the soggy green vineyards of Galicia on the north Atlantic coast to the baked Mediterranean south east. Spain's saving grace, viticulturally, is the average altitude of her vineyards, over 600 m (2,000 ft)...
Spain also has its own handsome array of indigenous grape varieties. Tempranillo produces some of the country's most admired red wines and is planted widely under several aliases. Spain's most planted grape variety was exported to France where it is known as Grenache. The Monastrell so common in the Levante is none other than fashionable Mourvèdre. Galicia's Albariño and Rueda's Verdejo are two white grape varieties of undisputable class and interest, Verdejo having been rescued only fairly recently from obscurity. There are many other candidates for such a rescue, with Rioja's Graciano and the Galician Godello being obvious examples...
Another common national characteristic is Spain's traditional fondness for American oak... But in one sense Spain's great gift to the world of wine is not a table wine at all but its incomparable late-fortified wine, a sure-fire appetite-whetter that has been much copied elsewhere, and often traduced even in its homeland Jerez: sherry. Spaniards are also extremely enthusiastic consumers of sparkling wine, mostly their own answer to champagne, Cava, the best examples of which are made in Penedès in north-east Spain." - Jancis Robinson
Map courtesy of Decanter