The 2010 Nobel peace prize placed on an empty chair

• The 2010 Nobel peace prize was on Friday placed on an empty chair in Oslo's city hall in a symbolic act to mark its award to Liu Xiaobo.
• He is in isolation in a prison in north-east China. Nor can the laureate's wife, Liu Xia, or his closest relatives were allowed by Chinese govt. to attend ceremony on this behalf
• It is the first time since 1936, when the German journalist and pacifist Carl von Ossietzky was stopped by Nazi authorities from travelling to Oslo, that the peace prize has been awarded in this way.
  
• On three other occasions -- Aung San Suu Kyi in 1991, Lech Walesa in 1983 and Andrei Sakharov in 1975 -- family members have had to collect the prize instead.