United States: Barack Obama, President
Russia: Dmitry Medvedev, President
China: Hu Jintao, President
Germany: Angela Merkel, Chancellor
United Kingdom: David Cameron, Prime Minister
France: Nicolas Sarkozy, President
Japan: Naoto Kan, Prime Minister
India: Manmohan Singh, Prime Minister
Brazil: Dilma Rousseff, President
South Africa: Jacob Zuma, President
Nigeria: Goodluck Jonathan, President
Canada: Stephen Harper, Prime Minister
Australia: Julia Gillard, Prime Minister
New Zealand: John Key, Prime Minister
Pope: Benedict XVI, Head of the Catholic Church
United Nations Secretary General: Ban Ki-moon
European Commission President: José Manuel Barroso
African Union Chairman: Jean Ping
Organization of American States Secretary General: José Miguel Insulza
Please note that this is not an exhaustive list and there are many other influential leaders around the world. Some changes may have occurred since 2011.