A painting worth almost $20 million hangs in a Spanish museum, but members of a La Mesa family say it should be hanging in their home.

The Cassirer family is suing the Spanish government for the return of the painting they say was stolen from them by the Nazis during World War II.

The painting is called "Rue Saint-Honore". It was painted in 1897 by Camille Pissarro, considered a master of impressionist painting. Claude Cassirer, 89, of La Mesa, was a young child in Germany in the 1920's and remembers seeing the painting hanging in his grandmother's home. He still has a photograph of the painting in his home, which is now a key piece of evidence in the lawsuit.

Cassirer says the painting was given to his grandmother, Lilly Cassirer, by the artist. The Cassirers were a prominent Jewish family in pre-war Germany and were patrons to many artists, including Pissarro. But in 1939, Lilly Cassirer and her husband scrambled to get out of Nazi Germany. According to the family's account, the only way she could secure exit visas was to sell the Pissarro to the Nazis for about $360. It was either that, or be shipped to a death camp.

Lilly Cassirer sold the painting and fled to England. After the war, she sued to get the painting back. The German government ruled the sale a bogus one and promised to return the painting, but it couldn't be found.

Exactly what happened to the masterpiece is a matter of speculation. But it is believed to have changed hands at least three times, travelled to three countries and two continents, including the U.S., before finally ending up at the Thyssen-Bornemisza Museum in Spain.

The family was overjoyed to discover it again after it surfaced in the museum's collection, but when they asked for the painting to be returned, the museum refused. So the Cassirers went to court to recover the painting.

Eleven years have now passed since the legal wrangling began. Claude Cassirer is almost 90 and his health recently declined due to his age. He is making a recovery at the California Special Care Center in La Mesa. But he and his wife vow to continue to fight for the painting as long as they are able. Their son, David Cassirer Highland, says it is a matter of justice.

Fox 5 contacted the Thyssen-Bornemisza Museum for its side, but officials declined to comment because the case is still in court.