Dr Allan Maca explores the legendary lost city of Xanadu in Inner Mongolia. Today very little remains of Kublai Khan's grand capital - a place that famous explorer, Marco Polo, described as one of the Marvels of the World. But now, with the help of satellite imagery and cutting-edge technology, we can finally uncover Xanadu's secrets, and bring this fabled city and its lavish palaces back to life.