German painter and sculptor Anselm Kiefer discusses the meanings behind some of his favorite materials, including straw, cow manure, and lead. He describes how he strives for fluidity and malleability in his work, though conservation can be a challenge.

Kiefer on art, history, and how they're both subjective:    • Anselm Kiefer: History is a clay  
Watch Kiefer apply molten lead to a canvas:    • In the studio with artist Anselm Kiefer