Question: At the 71st annual Venice International Film Festival, the Silver Lion Grand Jury Prize was won by a 2014 international co-produced documentary that is a companion piece to what?
Context: Kim Ki-duk ( ] ; born December 20, 1960) is a South Korean filmmaker noted for his idiosyncratic art-house cinematic works.  His films have received many distinctions in the festival circuit, making him one of the most important contemporary Asian film directors.  Major festival awards include Golden Lion at 69th Venice International Film Festival for "Pietà", Silver Lion for Best Director at 61st Venice International Film Festival for "3-Iron", Silver bear for Best Director at 54th Berlin International Film Festival for "Samaria" and Un Certain Regard prize at 2011 Cannes Film Festival for Arirang.  His most widely known feature is "Spring, Summer, Fall, Winter... and Spring" (2003), included in film critic Roger Ebert's Great Movies.  Two of his films served as official submissions for Academy award for best foreign language film as South Korean entries.  He has given scripts to several of his former assistant directors including Juhn Jai-hong ("Beautiful" and "Poongsan") and Jang Hoon ("Rough Cut"). Neon Bull (Portuguese: Boi neon ) is a 2015 Brazilian drama film directed by Gabriel Mascaro.  The film premiered at the 72nd Venice International Film Festival and won the Horizons (Orizzonti) - Special Jury Prize.  It was also shown in the Platform section of the 2015 Toronto International Film Festival, where it received an honorable mention from the jury.  At the 31st Warsaw International Film Festival it received the main prize of the International Competition, the Warsaw Grand Prix. Carl-Johan Westregård (born November 7, 1984) is a Swedish film director and visual effects artist.  His short film "Cams" premiered at the 71st Venice International Film Festival and was awarded the Special Jury Prize in the Lab Competition of the 2015 Clermont-Ferrand International Short Film Festival. The 71st annual Venice International Film Festival took place in Venice, Italy between 27 August to 6 September 2014.  The Swedish film "A Pigeon Sat on a Branch Reflecting on Existence" won the Golden Lion award.  Joshua Oppenheimer's "The Look of Silence" won the Silver Lion Grand Jury Prize. Sivas is a 2014 Turkish drama film directed by Kaan Müjdeci.  It was selected to compete for the Golden Lion at the 71st Venice International Film Festival where it won the Special Jury Prize.  The film was selected as the Turkish entry for the Best Foreign Language Film at the 88th Academy Awards but it was not nominated. 99 Homes is a 2014 American drama film directed by Ramin Bahrani, and written by Bahrani and Amir Naderi.  The film stars Andrew Garfield, Michael Shannon and Laura Dern.  Set in Florida, the film follows single father Dennis Nash (Garfield) and his family as they are evicted from their home by businessman Rick Carver (Shannon), forcing Nash to help Carver in evicting people out of their homes in exchange for their own home.  Bahrani dedicated the film to the late film critic Roger Ebert.  It competed for the Golden Lion at the 71st Venice International Film Festival.  It won Grand Prix at 2015 Deauville American Film Festival.  It also screened in the Special Presentations section of the 2014 Toronto International Film Festival.  The film was released in a limited release on September 25, 2015, by Broad Green Pictures. Belluscone: A Sicilian Story (Italian: "Belluscone - una storia siciliana" ) is a 2014 Italian docu-fiction film written and directed by Franco Maresco.  It was screened in the Horizons section at the 71st Venice International Film Festival, winning the Special Jury Prize. Trap Street () is a 2013 Chinese film written and directed by debut Chinese film director Vivian Qu, and starring Lu Yulai and He Wenchao.  It premiered at the 2013 Venice International Film Festival, where it was nominated for the prestigious "Luigi De Laurentiis Award".  It subsequently won the "Dragons and Tigers Award - Special Mention" and second place in the Award itself at the Vancouver International Film Festival in the same year, and the "Grand Jury Prize" at the Boston Independent Film Festival in early 2014. The Look of Silence (Indonesian: "Senyap" , "Silence") is a 2014 internationally co-produced documentary film directed by Joshua Oppenheimer about the Indonesian killings of 1965–66.  The film is a companion piece to Oppenheimer's 2012 documentary "The Act of Killing".  It was executive produced by Werner Herzog, Errol Morris, and Andre Singer.  It was nominated for the Academy Award for Best Documentary Feature at the 88th Academy Awards. Foxtrot (Hebrew: פוֹקְסטְרוֹט‎ ‎ ) is a 2017 Israeli drama film directed by Samuel Maoz.  It was screened in the competition section of the 74th Venice International Film Festival where it won the Grand Jury Prize Silver Lion.  It was also screened in the Special Presentations section at the 2017 Toronto International Film Festival.  It won the Ophir Award for Best Film, therefore becoming the Israeli entry for the Best Foreign Language Film at the 90th Academy Awards.
Answer: The Act of Killing