La Tour des chevaux bleus

Franz Marc painted his tower of four blue horses in 1913, stacking their bodies almost vertically, with crescent moons and a rainbow marked on the lead animal's flank. For Marc, blue stood for the spiritual and the masculine, and horses were his way of reaching a world purer than the human one. Within a year he was in uniform, and he was killed at Verdun in 1916, at 36. The picture's later story is stranger than the painting. The Nazis seized it as degenerate art, and after war veterans protested at attacking a fallen soldier's work it was pulled from the touring show. It passed through Hermann Göring's hands, and was last seen in Berlin in 1948. Since then no one knows where it is, and people are still looking for it.