"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. 

Washington's crossing has been the focus of a movie and countless books.

It was the first move in a surprise attack by revolutionaries in the pivotal battle at Trenton, starting on Christmas night 1776, both a strategic and symbolic triumph.

The oil on canvas portrays a country with wide-ranging roots. Men on the boat wear Native American and Scottish outfits, and there is a Black man still enslaved.

When it goes up for auction, it is expected fetch over $20 million.