Obama, Medvedev Find Curious Russian Photo-Op

On the second day of their summit to ease tensions in U.S.-Russia relations, Presidents Obama and Medvedev posed for a photo in front of an historic instrument of war.
It was a huge cannon dating back to Russia's Tsar Geodor in 1586. Called the Tsar Pushka (Tsar Cannon), it's positioned on the grounds of the Kremlin and is said to be over 17 feet long and weigh 38 tons. That's one big cannon.
There's a dispute over whether the cannon was ever fired or is just ceremonial. Wikipedia reports the weapon was analyzed by the Dzerzhinsky Military Academy and traces of gunpowder were found – suggesting it was fired at least once. But definelty not with the enormous two ton cannonballs positioned below its muzzle on the Kremlin grounds.

The cannon photo raises the question of how Mr. Obama can return the favor when Medvedev next makes a reciprocal visit to the White House. There are no historic weapons on the White House grounds to pose beside.
Perhaps they could have their picture taken next to the Obama girls swing set outside the Oval Office.