It is one of the most iconic photographs of the 20th century: an unidentified man stopping the advance of a convoy of tanks through Tiananmen Square.
Thirty years after the government's crackdown on students who filled the square demanding democratic reform, many young students today have never seen the photo.
Those who have seen it are reluctant to discuss it in public. Textbooks do not mention the violence that left hundreds, maybe thousands, of students dead near Tiananmen Square. The Chinese internet has been scrubbed of all but the official accounts.
