Question: Containing 498 shops, what shopping centre marks the beginning of the Westfield Sydney to Melbourne Ultramarathon?
Context: Westfield Sydney is a shopping centre operated by Scentre Group and located beneath the Sydney Tower in the Sydney central business district.  It is located on Pitt Street Mall and is adjacent to the Mid City Centre, The Strand Arcade and Stockland Glasshouse. Sanga is a community made up of people in mainly six villages in Nyashanu area of Buhera District, Zimbabwe.  It is within the traditional jurisdiction of Headman ("Sadunhu") Mabvuregudo and Chief ("Ishe") Nyashanu of the "Shava" totem.  Sanga is in between Masenga Mountain which is near Nyashanu Mission and Chiurwi Mountain.  The mountain, sometimes called Dzapasi, played a significant role as a demobilisation point of armed forces at the end of Zimbabwe’s Second War of Liberation, the Second "Chimurenga".  Sanga community has one service centre, called Sang which hosts the Sanga Cattle Sales Pens popularly known as Sanga Market, Sanga Police Station and grocery shops like Manjovha, Mutemahuku, Vhiriri, Rugare and others.  Sanga Market was traditionally a cattle trading point but now is a trading centre for cattle, small livestock, grains, hardware, groceries, clothes, kitchenware, mobile phones and various other accessories.  Nearby service centres include Mumbijo Shopping Centre, also known as Chipoka, which is along Fari Road, Mashingaidze Shopping Centre at the intersection of Nyashanu Mission Road, Vhiriri Road and Fari Road; and Matsvai Changamire Shopping Centre.  At Mumbijo you find shops like Maunganidze, Mugumbate or Tirivavi, Matsvai, Vhiriri and Mukuvare (formerly Topodzi).  At Mashingaidze there are shops like Mashingaidze, Gavi, Kwaramba, Dondo and Maponda.  At Matsvai there are shops like Musengi and others.  Two service centres were proposed in 2014 at Sanga School turnoff and at Madhume Road turnoff, near Muchada Bus Stop but these were not approved by Buhera District Council.  Other services include grinding mills that are found at the service centres or in the villages. Stockland Glasshouse is a shopping centre on Pitt Street Mall in the Sydney central business district, Australia.  Located on the corner of King Street and the Pitt Street Mall, it is near The Strand Arcade, Mid City Centre, Sydney Arcade and Westfield Sydney. Mylly (lit.  mill) is a shopping centre in Raisio, Finland.  The shopping centre has nearly a hundred shops, banks, and other services on an area of 63000 m2 , and is as such the largest shopping centre in the Turku region and fourth largest in Finland outside the Helsinki region.  Mylly was opened in October 2001 and in 2008 the annual sales was 167 million euros.  The shopping centre was expanded in 2016, adding an additional section containing a number of businesses. Bluewater Shopping Centre (commonly referred to as Bluewater) is an out-of-town shopping centre in Stone (postally Greenhithe), Kent, England, outside the M25 Orbital motorway, 17.8 mi east south-east of London's centre.  Opened on 16 March 1999 in a former chalk quarry after ten years of building works, the site including car parks occupies 240 acres and has a sales floor area of 154,000 m (1,600,000 ft) over three levels, making it the fourth-largest shopping centre in the UK (after the MetroCentre, Trafford Centre and Westfield Stratford City).  Elsewhere in Europe only Istanbul's Cevahir Mall and Vienna's (Vösendorf) Shopping City Süd are bigger.  The floor plan is a triangular shape with 330 stores, including 3 anchors, 40 cafés and restaurants, and a 13-screen cinema.  The centre employs 7,000 people and serves over 27 million visitors a year.  A main rival is the Lakeside Shopping Centre and its two retail parks by road 8 mi away in West Thurrock, Essex, just across the River Thames or 3.2 mi point-to-point. Westfield Tea Tree Plaza is a large shopping centre located in Modbury serving as a shopping hub for Adelaide's growing north eastern suburbs.  It is linked to the city by Adelaide's unique O-Bahn system, which terminates at the Tea Tree Plaza Interchange.  There is a smaller shopping centre building called Tea Tree Plus slightly to the north of the main centre.  Major tenants include Myer, Harris Scarfe, Target, Kmart, BIG W, Woolworths, Coles, Aldi and Hoyts Cinemas. With 245 stores, Tea Tree Plaza is the second largest shopping centre in Adelaide, only Westfield Marion is larger. Westfield Parramatta is a shopping centre in Parramatta, a city within the Greater Sydney Metropolitan area Sydney, New South Wales, Australia.  The centre is owned and managed by The Westfield Group.  In July 2014, the Westfield Group became two companies Scentre Group and Westfield Corporation.  This shopping centre is now managed by Scentre Group.  It has a net leasable area of approximately 137,407m² and contains 498 shops built over five levels, making it Australia's fourth largest shopping centre by Gross Leasable Area (GLA). Athlone Towncentre is a shopping centre located in Athlone, County Westmeath, Ireland.  The shopping centre is the largest shopping centre in the Irish midlands with over 140,000 sq meters of retail space consisting of 60 high end retail shops.  The Shopping centre is located in the heart of Athlone town enclosing a site on Dublin Gate Street and Gleeson Street.  The Shopping Centre opened in 2007.  The 4 star Sheraton Hotel adjoins the site and consists of 161 beds.  Anchor tenants include Marks and Spencer, River Island, Tommy Hilfiger, Topshop, Next, H&M, Monsoon amongst many more. The Westfield Sydney to Melbourne Ultramarathon was an annual ultramarathon foot race held between 1983 and 1991.  It was sponsored by the Westfield Group, with the start being at Westfield Parramatta shopping centre and the finish at Westfield Doncaster shopping centre (formerly known as "Doncaster Shoppingtown"). Elmvale Acres Shopping Centre is an open-air mall located in the Elmvale Acres neighbourhood of Ottawa, Ontario, Canada.  It opened in 1961, making it one of the oldest shopping centres in the city.  The mall is just a short 10-minute drive south of St. Laurent Shopping Centre.  The shopping centre is also just a 3-minute drive from the Canadian Museum of Science of Technology (closed until 2017).  The Smythe Medical Centre is located just across from the north end of the mall.  The mall is bounded by Smythe Road to the north, Othello Avenue to the west, Russell Road to the east, and St. Laurent Boulevard to the south.  The shopping centre has approximately 60 shops and services including Dollar Plus, LCBO, Loblaws, Rexall Pharma Plus, Royal Bank, The Beer Store, and the Ottawa Public Library.  The shopping centre is adjacent to the Elmvale Transit Station.  The size of the total complex is 147,332 square feet.  The shopping centre is currently owned by Rio-Can Real Estate Investment Trust.
Answer: Westfield Parramatta