John Simpson has reported from the frontline for the BBC for 50 years - and has seen the world change enormously during that time. In 1989 he reported on China's Tiananmen Square massacre - how has China changed since then? #ThenandNow | BBC Panorama | Facebook

On June 5, 1989, photographer Charlie Cole put what would become one of the most iconic photos of the 20th century in the holding tank of his hotel toilet. Luckily, the Chinese Public Security Bureau never found it, the camera film was never flushed, Cole made his Newsweek deadline, and the rest is history. On the 33-year anniversary of one unidentified protestor boldly staring down a column of government tanks in Tiananmen Square, stream FRONTLINE | PBS' "The Tank Man" documentary online and on