Question: What city held the 1956 Summer Olympics where Robert O'Brien competed in sprint canoe?

Context paragraphs:
Brian Morton (canoeist): Brian Morton (born 1 January 1970) is an Australian sprint canoeist who competed from the mid-1990s to the early 2000s (decade).  He competed in four World Sprint Canoe Championships 1995-1999 and two Summer Olympics; Atlanta 1996 and Sydney 2000.  He earned his best finish of third in the Men's K-4 1000m event in the 1997 World Sprint Canoe Championships in Nova Scotia, Canada.  His best Olympic placing was ninth in the K-4 1000 m event at Atlanta in 1996.

List of Dutch Olympic cyclists: This is a list of all Dutch cyclists who competed at the Summer Olympics.  As of 2012 events in four cycling disciplines (BMX, mountain biking, road cycling and track cycling) have been competed at the Summer Olympics.  Dutch cyclist did not competed at the 1896, 1900 Summer Olympics, 1904 Summer Olympics and 1912 Summer Olympics and boycotted the 1956 Summer Olympics.

Norman Lane: Norman D. Lane (November 6, 1919 – August 6, 2014) was a Canadian sprint canoeist who competed in the late 1940s and early 1950s.  Competing in two Summer Olympics, he won a bronze in the C-1 10,000 m event at London in 1948.  He competed in the 1952 Helsinki Olympics and finished fifth.  His brother Ken Lane was a medallist at the 1952 Games in sprint canoe.

Michael Scarola: Michael "Mike" Scarola (born January 26, 1976) is a Canadian sprint canoer and marathon canoeist who competed in the early 2000s.  He won a bronze medal in the C-2 1000 m event at the 2002 ICF Canoe Sprint World Championships in Seville, Spain and also won a silver medal in C-2 (canoe doubles) at the ICF World Marathon Canoe Kayak Championships in Dartmouth, Nova Scotia in 2000.  Mike also finished sixth in the C-2 1000 m event at the 2004 Summer Olympics in Athens.  Mike was a member of Canada's Senior National Sprint Canoe Kayak Team for 7 years.

Robert O'Brien (canoeist): Robert O'Brien (born June 6, 1933) is an American sprint canoer who competed in the late 1950s and early 1960s.  Competing in two Summer Olympics, he earned his best finish of 11th in the K-1 10000 m event at Melbourne in 1956.

Venues of the 2000 Summer Olympics: For the 2000 Summer Olympics, a total of thirty sports venues were used.  After Melbourne hosted the 1956 Summer Olympics, Australia made several bids for the Summer Olympics before finally winning the 2000 Summer Olympics by two votes over Beijing, China.  Venue construction was set at the Homebush Bay area of Sydney in an effort to rehabilitate the land.  Environmental studies of the area in the early 1990s forced remediation to be used for about a fifth of the site selected.  Fifteen new venues were constructed for the Games.  During the games, 137 cars were removed from the streets of Sydney before the start of the women's marathon while the last day of the canoe sprint finals were delayed by six hours due to heavy winds at the Regatta Centre.  Many of the venues used for the 2000 Games continue to be in use as of 2017.

Natalya Sergeyeva: Natalya Sergeyeva (born May 3, 1976) is a Kazakhstani sprint canoe racer who competed from the mid-2000s.  At the 2004 Summer Olympics in Athens, she was eliminated in the semi-finals of the K-2 500 m event while being disqualified in the heats of the K-1 500 m event.  At the 2012 Summer Olympics she was eliminated in the semi-finals of the K-1 200 m.  In the K-1 500 m she reached the B Final.

Canoeing at the 1956 Summer Olympics: At the 1956 Summer Olympics in Melbourne, nine events in sprint canoe racing were contested.  The program was unchanged from the previous two Games in 1948 and 1952.  The competition was held on Lake Wendouree in Ballarat.

1956 Summer Olympics: The 1956 Summer Olympics, officially known as the Games of the XVI Olympiad, were an international multi-sport event which was held in Melbourne, Victoria, Australia, in 1956, apart from the equestrian events, which were held five months earlier in Stockholm.  The 1956 Games were the first to be staged in the Southern Hemisphere and Oceania, as well as the first to be held outside Europe and North America.  Melbourne is the southernmost city to host the games.  Equestrian events could not be held in Australia due to quarantine regulations.  This was the second Olympics not to be held entirely in one country, the first being the 1920 Summer Olympics, which Antwerp, Belgium, co-hosted with Amsterdam and Ostend.

Russell Dermond: Russell Charles "Chick" Dermond (December 31, 1936 in Fair Lawn, New Jersey – May 9, 2015) was an American sprint canoer who competed in the late 1950s and early 1960s.  His early years were spent in the American Canoe Association as a flatwater racer and began in the wooden "peanut," which was the predecessor of modern kayaks and C boats.  A many-time national champion, he competed in the 1956 and 1960 Olympics.  At the 1956 Summer Olympics in Melbourne, he was eliminated in the heats of the K-2 1000 m event.  Four years later in Rome, he was eliminated in the repechages of the K-1 4 × 500 m event.  He attended as Team Manager in 1972 and later served on the U.S. Olympic Committee.  He was very active in the ACA, serving in a number of governing positions including Sugar Island in the Thousand Islands and Lake Sebago in Harriman State Park.

Supporting paragraphs: Robert O'Brien (canoeist) 1956 Summer Olympics
Answer: Melbourne