The need for and location of a second airport serving Sydney, Australia was the subject of much debate. The new airport would supplement or replace the city's existing Kingsford Smith Airport. Governments had debated the issue since the 1940s, but for decades had not pursued anything beyond preliminary investigations and precautionary land acquisition. The debate was settled in the 2010s when a site at Badgerys Creek was selected. With an estimated cost of between $6 and $8 billion, construction of the airport began in September 2018 and will be completed in 2026.