A tiny 5-inch red-chalk sketch of a man's foot is now linked to Michelangelo's Sistine Chapel ceiling. Auction house Christie's says it could fetch at least $2 million, becoming the most expensive foot drawing ever sold. Specialists believe it's a study for the Libyan Sibyl, one of the iconic figures painted around 1511. The work surfaced when an anonymous California owner, who inherited it in 2002, sent photos to Christie's. Scientific tests confirmed the paper matched 16th-century examples and tied it to a related Michelangelo study in the Met. It's one of only two known Michelangelo drawings for the Sistine ceiling still in private hands. With only about 600 surviving works — many destroyed on Michelangelo's own orders — the rare sketch is heading to auction in February.