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Fifty years after it was seized by North Korea, the USS Pueblo is the only U.S. Navy ship held captive by a foreign government. And though mostly forgotten in the United States, the "Pueblo Incident" for North Korea remains a potent symbol of military success.

The spy ship and captured 50 years ago this week sits in a frozen river on the edge of the "Victorious Fatherland Liberation War Museum" in Pyongyang, where thousands of North Koreans are brought each day to hear the North's version of how their country defeated the Americans in the 1950-53 Korean War.

State media have played up the anniversary as a milestone in North Korea's struggle against the United States.

The ship has been extensively refitted to heighten its propaganda impact.