Cities in Canada and very much the east coat before 60's was very strong on mix use buildings like this http://farm7.staticflickr.com/6045/6...4ec21bae_b.jpg
Where in US in 20's , 30's , 40's and 50's that was not case .
Other thing very alien to the US is tower in park concept a 15 to 20 story apartment place in the suburbs in low density suburban sprawl single family homes that was very popular in the 60's and 70's and was not popular in the 80's and 90's and now making a come back with high-rise condos.
Other thing very alien to the US is Canada downtown core is more mix use where has in the US this is not always the case .In the past 10 years and very much so 8 years there is more redevelopment in the downtown area like in Toronto , Calgary ,Vancouver so on. And big high-rise condos boom .
The US downtown core mostly office ,businesses and entertainment and not some thing a lot people want to live.The thought of living in medium or high density in down-town or high-rise condos is very alien to the US.
There is a lot of high-rise condos and infill going on in the suburbs and in place now .