Three memories I have of the first time I visited Madrid: the relentless elegance of the women in the fashionable areas, the sumptuous gazpacho at the Ritz Madrid, and seeing “Las Meninas” in the Prado. Ask an artist or a philosopher today to name the greatest painting in the world and the chances are they will say “Las Meninas” (The Maids of Honor) by Diego Velasquez. As a history of art student, I would gaze at the reproductions in my Thames and Hudson art books. I wasn’t sure why this was the most written about painting in Western civilization. Velázquez’s supreme painting hangs in the high octagonal room at the heart of the Prado Museum. It is recognized as a masterpiece of the Spanish Golden age, one of the pivots on which art history turns. I gasped in sheer wonder at the first sight of it. Velázquez: Come Into My …