Anyone who has visited Beijing's Forbidden City, the historic former home of China's emperors during the Ming (1368-1644) and Qing (1644-1911) dynasties, knows even an entire day inside the massive architectural masterpiece is barely enough time to scratch the surface.

And for a president on a tight schedule, a whistle-stop tour of the landmark was always likely to be more of a photo opportunity than a learning experience.

But for United States President Barack Obama, a visit to the world-famous complex was not to be missed, no matter how limited his time.