<p>One of the United States' most advanced nuclear submarines returned to port in Washington state this week flying a Jolly Roger, a move steeped in maritime lore and mystery.</p>
<p>The images of the USS Jimmy Carter, a Seawolf-class nuclear-powered submarine passing through the Hood Canal, were posted to a Pentagon media site and Twitter page. They show the skull and bones flying beside the American flag, the Washington Post reported.</p>