From the Colossus of Rhodes to the hanging gardens of Babylon, we visit the seven wonders of the ancient world with author and historian Bettany Hughes; and from jewels to jumbo jets, a history of diplomatic gift giving; journalist Ed Wong on how travelling China with his father taught him that his family story is deeply entwined with China's rising power; 50 years of Papua New Guinean independence. Plus two new takes on Australian history with Professor Mark McKenna and Annabel Crabb.