The entire City of Kingston Ontario should be a UNESCO World Heritage Site.

In the year 2007, the Rideau Canal and Kingston Fortifications were inscribed as Cultural UNESCO World Heritage Sites.
The Kingston Fortifications
Fort Henry
Fort Frederick
Cathcart Tower
Shoal Tower
Murney Tower

 In order to be nominated as a World Heritage Site, the buildings within that city have to already  be classified.
Bellevue House, the home of Canada's first Prime Minister Sir John A. Macdonald is a National Historic Site of Canada.
The Kingston Penitentiary was a Classified Federal Heritage Building of Canada complex, and is currently a National Historic Site of Canada. Kingston Pen would have to be dynamited to remove  perimeter walls, guard towers and buildings---so that high rise condos and townhouses could be built on the property.
The final scene in the 1978 movie Superman, and Alias Grace were filmed at the Pen.

The Prison for Women, located opposite the Pen, was a Recognized Federal Heritage Building in Canada. There are currently plans to destroy the interior of P4W to create space for high-end housing, student housing and commercial entities. And the politician who represents the Village of Portsmouth wants to see a high rise on the land that surrounds P4W.

Old Kingston Post Office - National Historic Site of Canada.

Another federal penitentiary in Canada may be decommissioned and sold to developers

Photo from 650 CKOM.

Photo from paNOW.

See the article "Feds should consider replacing 'old and outdated' Saskatchewan Penitentiary--John Howard Society" by Alex Macpherson, Saskatoon Starphoenix, November 2, 2017.
Acccording to the 2007 document "A Roadmap to Strengthening Public Safety"...

                      "Yesterday's infrastructure does not meet today's needs". 
Recommendation 98: The Panel recommended that CSC pursue undertaking capital and operating investments in a new type of regional penitentiary complex that responds to the cost efficiency and operational deficits of the current infrastructure".

Recommendation 100: The Panel recommends that in the interim, CSC institute clear criteria to minimize authorization of retrofit projects".
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The Don Jail in Toronto was preserved. The prison was featured in the television show "Orphan Black" and the Tom Cruise movie "Cocktail"; the jail was The Cell Block Bar in the film.