"Washington Crossing the Delaware" going up for auction and could sell for over $20 million

One of the most famous paintings of the American Revolution and likely the most famous image of George Washington is going up for sale.

"Washington Crossing the Delaware," which hung in the White House for parts of four decades, will go up for auction at Christie's in May.

The painting was done by a German American artist named Emanuel Leutze. It is not the only image of the crossing. A larger version takes up an entire wall at the Metropolitan Museum of Art in New York City.