The vineyards of Mendoza, Argentina's wine capital, oases of greenery set in a semi-arid desert, exist only because of altitude: that at which Argentine vineyards thrive would be unthinkable in Europe: from 700 to 1,400 m and even 2,400 m in a northern case. At this elevation, nighttime temperatures are consistently low, allowing the production of strongly fragrant and intensely colored grapes. Soils are relatively recent and alluvial with high proportions of sand in many areas. The intensity of the wines thus derives not so much from the subsoil, but from the intense sunlight, dry air and diurnal temperature range at these high altitudes. For the time being, national wine fame is anchored by the second most cultivated red wine variety, malbec (the first being bonarda), introduced in Mendoza in the mid-19th century.