The Farm seen from the air
This photo, taken around 1950, shows CBNRC/CSE's second headquarters, the Rideau Annex (circled in red), as seen from the air looking southeast from downtown Ottawa. (Click on the photo for a larger view.)
The Victoria Memorial Museum (now the Canadian Museum of Nature) is the dark building on the far right, and the Lord Elgin Hotel is the light-coloured multi-storey building at the bottom left. Several of the "temporary" office buildings built during the Second World War can be seen just beyond the Lord Elgin.
Although it was less than four kilometres from Parliament Hill, the Rideau Annex was located in farm country when it was first occupied by CBNRC -- hence its nickname, "the Farm". Plans were already underway by 1950 for the area's development, however, and within a few years housing tracts began to fill what is now the Riverview neighbourhood.
More on the history of the Rideau Annex here.