New York Metropolitan Area     
Population Density   -   689.8/km2
https://en.wikipedia.org/wiki/New_York_metropolitan_area
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Chicago Metropolitan Area    
Population Density   -   509/km2
https://en.wikipedia.org/wiki/Chicago_metropolitan_area
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Greater Los Angeles Area      
Population Density   -   212.4/km2
https://en.wikipedia.org/wiki/Greater_Los_Angeles_Area
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Sydney (Australia) metropolitan area 
 Population Density   -   372.4/km2 
http://www.cityofsydney.nsw.gov.au/learn/research-and-statistics/the-city-at-a-glance/metropolitan-sydney
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Greater Toronto Area           
 Population Density   -   849/km2
https://en.wikipedia.org/wiki/Greater_Toronto_Area
And more than half of GTA is “Green Belt”. If you remove the greenbelt area from the equation  then the population density of the GTA could be more than 1600/km2.  Simply there is no space to build. Thus sky rocketing land prices. Thus sky rocketing home prices.