Pietà

Michelangelo was 24. The Virgin appears impossibly young (younger than her dead son) — Michelangelo said her purity had preserved her. Christ's body drapes across her lap with a horizontal weight that pulls the whole pyramid downward; her left hand is turned palm-up in a gesture of open, unanswerable grief. It's the only work Michelangelo ever signed — the sash across her chest, added after he overheard someone credit the sculpture to a rival. Behind bulletproof glass since 1972.