Question: One Queensbridge and Australia 108 are two buildings currently under construction aiming to be the tallest building in which city?

Context paragraphs:
555 California Street: 555 California Street, formerly Bank of America Center, is a 52-story 779 ft skyscraper in San Francisco, California.  It is the fourth tallest building in the city, the largest by floor area, and a focal point of the Financial District.  It is the 69th tallest building in the United States, one foot taller than One Worldwide Plaza in New York City and just 1 foot shorter than the 68th tallest building in the USA, which is also owned by Bank of America, the Bank of America Center in Houston, Texas at 780 ft (238 m), and just 2 feet shorter that the 67th tallest building in the USA, 30 Hudson Street in Jersey City, New Jersey at 781 ft (238 m).  Some sites round the heights of all four buildings to 780 ft (238 m) making those four buildings tied as the 67th tallest buildings in the country.

List of tallest buildings in Europe by year: This list of tallest buildings in Europe by year ranks the tallest buildings in Europe by year according to height.  Only the ten tallest buildings are included for all decades other than those buildings currently tallest in Europe.  The current tallest building in Europe is the Mercury City Tower in Moscow, Russia, which rises 339 m and was completed in 2012.  The 463 m Lakhta Center in Saint Petersburg, Russia, will become Europe's tallest building when completed in 2017.

List of tallest buildings in Corpus Christi: This list of tallest buildings in Corpus Christi ranks high-rises in the U.S. city of Corpus Christi, Texas by height.  The tallest building in Corpus Christi is the 28-story One Shoreline Plaza South Tower, which rises 411 feet (125 m) and was completed in 1988.  It also stands as the tallest building in Texas south of San Antonio.  The building is located on a complex which also contains the second tallest building in the city at 375 feet (114 m).  The third tallest building is the Frost Bank Plaza.  It stood as the city's tallest building from 1983 to 1988.

List of tallest buildings in Adelaide: This list of tallest buildings in Adelaide ranks the tallest buildings in Adelaide, South Australia by height.  The tallest building in Adelaide is currently the 31–story Westpac House, which rises 132 m and was completed in 1988, as of October 2013 it is Australia's 115th tallest building.  There are numerous projects either underway or planned in Adelaide, if constructed, Frome Central Tower 1 (11-27 Frome Street) would reach 134 m , therefore becoming the city's tallest building.  The tallest approved building in Adelaide is the Sofitel Hotel (104-108 Currie Street), which will be 115 m , it is planned to become the city's second tallest building upon completion.  Height restrictions–enforced since the 1990s–have limited the amount of skyscrapers constructed in the city although they have been eased in recent times.

One Queensbridge: One Queensbridge (or Crown Queensbridge) is an approved mixed–used supertall skyscraper to be located in the Southbank precinct of Melbourne, Australia.  When built, the skyscraper will become the tallest building in Melbourne, surpassing the height of Australia 108, and the tallest building in Australia, eclipsing the height of Q1.  In addition to being the tallest, the development is one of the biggest single–building projects in Australia, encompassing 300376 sqm of floor area.

Australia 108: Australia 108 (previously 70 Southbank Boulevard) is a residential supertall skyscraper currently under construction in the Southbank precinct of Melbourne, Victoria, Australia.  When completed, it will become the tallest building in Australia by roof height, surpassing the Eureka Tower, and the second-tallest building in Australia by full height, surpassed by Q1.  The project consists of a 317 m apartment building with 1,105 apartments over 100 floors.  Construction commenced in 2015, with completion expected in 2020.

List of tallest buildings in Chicago: Chicago, the third-largest city in the United States, is home to 1,315 completed high-rises, 44 of which stand taller than 600 ft .  The tallest building in the city is the 108–story Willis Tower (formerly the Sears Tower), which rises 1451 ft in the Chicago Loop and was completed in 1974.  Sears Tower was the tallest building in the world from its completion, and remained the tallest building in the United States until May 10, 2013 when it was overtaken by One World Trade Center in New York City.  The second-, third- and fourth-tallest buildings in Chicago are the Trump International Hotel & Tower, the Aon Center and the John Hancock Center, respectively.  Of the ten tallest buildings in the United States, four are located in Chicago.  s of 2013 , the entire city had 105 buildings at least 500 ft tall.

U.S. Bank Tower (Los Angeles): U.S. Bank Tower, formerly Library Tower and First Interstate Bank World Center, is a 1018 ft skyscraper at 633 West Fifth Street in downtown Los Angeles, California.  It is the third tallest building in California, the second tallest building in LA, the fifteenth tallest in the United States, the third tallest west of the Mississippi River after the Salesforce Tower and the Wilshire Grand Center, and the 92nd tallest building in the world, after being surpassed by the Wilshire Grand Center.  Because local building codes required all high-rise buildings to have a helipad, it was known as the tallest building in the world with a roof-top heliport from its completion in 1989 to 2004 when Taipei 101 opened.  It is also the third tallest building in a major active seismic region; its structure was designed to resist an earthquake of 8.3 on the Richter scale.  It consists of 73 stories above ground and two parking levels below ground.  Construction began in 1987 with completion in 1989.  The building was designed by Henry N. Cobb of the architectural firm Pei Cobb Freed & Partners and cost $350 million to build.  It is one of the most recognizable buildings in Los Angeles, and often appears in establishing shots for the city in films and television programs.

List of tallest buildings in Omaha, Nebraska: The tallest buildings in Omaha, Nebraska include towers for Woodmen of the World and the First National Bank of Omaha.  Omaha's tallest building is the 634 ft (193 m), 45-story First National Bank Tower.  Completed in 1969, the 478 ft (146 m), 30-story tall Woodmen Tower was the tallest until the construction of the First National Bank Tower.  While most of the city's tallest buildings are located in Downtown Omaha, several are located in Midtown Omaha.  These include the 22-story, 320 ft (98 m) Masonic Manor, currently the third tallest building in the city, and the 285 ft (87 m), 14-story Mutual of Omaha Building.  The University of Nebraska Medical Center is located in midtown and among its rapidly expanding campus is the 230 ft Lied Transplant Center.  There was also a proposal to build a 373 ft (114 m) Wallstreet Tower Omaha on the site of the old Union Pacific Headquarters.  If the tower was completed, it would have been the city's third tallest building, however plans were eventually scrapped for the idea.

List of tallest buildings in Pennsylvania: This lists the tallest buildings in Pennsylvania, over 120 meters (400 feet), ranked by height.  The tallest building in Pennsylvania is the 58-story Comcast Center located in Philadelphia, which at 975 feet (297 meters) is currently the 20th-tallest building in the United States.  It was topped out on June 18, 2007, to become the tallest building in Philadelphia and the state.  The currently under construction Comcast Technology Center in Philadelphia, which will rise 60 stories and 1121 feet tall, will be the tallest building in Philadelphia and the state of Pennsylvania upon its completion in 2018.  It will also be the 9th tallest building in the United States.  All of the buildings over 120 meters are in Philadelphia and Pittsburgh; 30 are in Philadelphia and 16 are in Pittsburgh.

Supporting paragraphs: One Queensbridge Australia 108
Answer: Melbourne