In 1980 Kiefer began to make fewer watercolors and turned to what he called "gouaches." "Brünnhilde Sleeps" and "Siegfried's Difficult Way to Brünnhilde" demonstrate how he started with photographs he had taken and then worked over them with acrylic and other opaque materials. Kiefer used many of his photographs of abandoned railway beds, some with their ties missing. He was attracted to their deep perspective as well as the way they evoke our historical awareness of where railways in eastern Europe sometimes led. "We see railroad tracks anywhere and think about Auschwitz," he said.