Lebreton.

  Lebreton is part of the Parliamentary Precinct which includes the Parliament Buildings, Parliament Hill, Wellington Street facing the Hill, Library and Archives, Supreme Court, Confederation Square, the northern half of the Sparks Street Mall and the Conference Centre where I was employed.
Museums, federal government buildings, commemorative statues, playgrounds and public festivals (for example Bluesfest) are appropriate for the Flats. Deputy Prime Minister Erik Nielsen created the NILM in order to keep federal properties federal.
National Interest Land Mass properties in the National Capital Region:
Lebreton Flats.
Experimental Farm on Carling Avenue.
The 2,965 acre Greenbelt Research Farm in Nepean bordered by Hunt Club Road, Woodroffe Avenue, Fallowfield Road and Greenbank Road.
Gatineau Park
The Greenbelt - 14,000 hectares.( City of Ottawa White Paper on Development in the Greenbelt - May 27, 2008 - Development Scenarios - "It is estimated that of the 20, 800 hectares in the Greenbelt, at least one quarter (approximately 5,560 hectares) might be eligible for development consideration if the Greenbelt designation was removed and development policies of the City's Official Plan were applied to those lands.")
When the Hon. Jim Prentice was the Minister of the Environment, he refused to sell any Greenbelt land to the City of Ottawa. Also part of the National Interest Land Mass:
Victoria Island.
Shoreline behind Parliament Hill.
Chambers Building, Elgin and Queen.
Confederation Square.

Pts of Wellington in front of Chateau Laurier and the Conference Centre and land to the E of the Conference Centre; also land W of Wellington between Rideau Canal Lock and the Chateau Laurier and Major Hill Park. Also, approach to the Alexandra Bridge and the new Art Gallery site.
Lady Grey Drive and the Ottawa River W of Sussex Drive.

Daly Building, corner of Rideau and Sussex.
8 parcels of land E of Sussex (Mile of History) from Rideau Street to Macdonald Cartier Bridge.
Pt of the Mint property W of Sussex Drive.

Small park on W side of Sussex Dr. S of the Macdonald Cartier Bridge,
2 parcels W of Sussex Drive N of Macdonald Cartier Bridge. Parking lot at Earnscliffe and water lot.
4 parcels on the Rideau River around City Hall.
4 parcels E of Sussex Drive between Stanley Ave. & Rideau Gate.

PM's residence.
7 Rideau Gate (Guest House.)
G.G.'s residence, Rideau Hall.
Ottawa River Parkway, Wellington Street to Carling Avenue.
There is a precedent for converting large parcels of government property into parkland:

House of Commons Debates  Ottawa February 23, 1994.
Hon. Charles Caccia (Davenport, Toronto, Ontario.) Liberal.
     "Mr. Speaker, my question is for the Minister of National Defence. Will the minister tell the House how he intends to proceed in ensuring that the Downsview base in Toronto is owned by the public in perpetuity, enjoyed as an open space, an open forest with recreational and educational facilities? This would provide enjoyment for Canadians interested in nature studies and urban dwellers seeking relaxation in a green environment. Will the lands be designated to become our first national urban forest?"
Hon. David Collenette (Minister of National Defence and Minister of Veterans Affairs.)
     ".....The Prime Minister should be thanked for giving in perpetuity a large urban recreational greenspace for the benefit of Torontonians for years to come. I believe what the government is saying here is that there is an alternative to paving over land and buildings, especially in high density areas. This is a plan to have the ownership of these lands retained by the Department of National Defence and developed for the benefit of all Torontonians recreationally...in conjunction with my colleague the Minister of Canadian Heritage responsible for Parks Canada and my colleague the President of the Treasury Board so that we can truly create a unique area for the benefit of all people.

 Lebreton is 4,450 feet, or less than a mile from the Peace Tower on Parliament Hill. (Hon. George McIlraith, Minister of Public Works, November 23, 1967, House of Commons.)
Prime Ministers of Canada and Members of Parliament were adamant that no buildings higher than the Peace Tower would be constructed on or near the Parliamentary Precinct.
House of Commons Debates   Ottawa   November 2, 1967.
Mr. Stanley Knowles (Winnipeg North Centre, Manitoba.)
     "Mr. Speaker, may I direct a question to the Minister of Public Works. Now that the commencement of construction of the national defence tower in Lebreton flats has been postponed, will the government consider the question of the height of this proposed building in the hope that it will not be as high as the Peace Tower?"
 The National Capital deserves a Central Park, a Hyde Park.